PCI bus frequency e. How to overclock a processor: the practical side of the issue. Information programs and utilities

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Chipset and bus overclocking parameters

By increasing the frequencies of the chipset and buses, you can raise their performance, but in practice it is often necessary to set fixed values ​​of these frequencies in order to avoid their excessive increase when overclocking the processor.

This parameter changes the frequency of the HT (HyperTransport) bus, through which AMD processors communicate with the chipset. As values this parameter multipliers can be used and the selected multiplier must be multiplied by the base frequency (200 MHz) to calculate the actual frequency. And in some BIOS versions, instead of multipliers, you need to select the HT bus frequency from several available values.

For the Athlon 64 family processors, the maximum NT frequency was 800-1000 MHz (multiplier 4 or 5), and for Athlon P / Phenom II processors - 1800-2000 MHz (multiplier 9 or 10). When overclocking, the multiplier for the HT bus sometimes has to be lowered so that after raising the base frequency, the HT frequency does not go beyond the permissible limits.

The parameter sets the frequencies of the AGP and PCI buses.

Possible values:

□ Auto - frequencies are selected automatically;

□ 66.66 / 33.33, 72.73 / 36.36, 80.00 / 40.00 - frequency of AGP and PCI buses, respectively. The default is 66.66 / 33.33, while others can be used for overclocking.

This parameter allows you to manually change the frequency of the PCI Express bus.

Possible values:

□ Auto - the standard frequency is set (usually 100 MHz);

□ 90 to 150 MHz - The frequency can be manually set, and the adjustment range depends on the motherboard model.

The parameters allow you to adjust the offset of the clock signals of the processor (CPU), as well as the north (MCH) and south (ICH) bridges.

Possible values:

□ Normal - the optimal value will be automatically set (recommended for normal operation and moderate acceleration);

□ from 50 to 750 - the amount of clock signals offset in picoseconds. The selection of this parameter can improve the stability of the system during overclocking.

The parameter is used in some motherboards to set the operation mode of the north bridge of the chipset depending on the FSB frequency.

Possible values:

□ Auto - chipset parameters are adjusted automatically (this value is recommended for computer operation in normal mode);

□ 200 MHz, 266 MHz, 333 MHz, 400 MHz - FSB frequency for which the chipset operating mode is set. Higher values ​​increase the maximum possible FSB frequency during overclocking, but decrease the chipset's performance. The optimal value of the parameter during overclocking usually has to be selected experimentally.

In addition to the processor and memory voltage, some motherboards also allow you to adjust the voltage of the chipset components and signal levels. The names of the corresponding parameters may differ depending on the manufacturer of the board. Here are some examples:

□ Chipset Core PCIE Voltage;

□ MCH & PCIE 1.5V Voltage;

□ PCH Core (PCH 1.05 / 1.8);

□ NF4 Chipset Voltage;

□ PCIE Voltage;

□ FSB OverVoltage Control;

□ NV Voltage (NBVcore);

□ SB I / O Power;

□ SB Core Power.

Practice shows that changing the indicated voltages in most cases does not give a noticeable effect, so leave these voltages at Auto (Normal).

When the components of a modern computer operate at high frequencies, an undesirable electromagnetic radiation which can interfere with various electronic devices. To slightly reduce the magnitude of the radiation pulses, spectral modulation of the clock pulses is used, which makes the radiation more uniform.

Possible values:

□ Enabled - clock modulation mode is enabled, which slightly reduces the level of electromagnetic interference from system unit;

□ 0.25%, 0.5% - modulation level in percent (set in some BIOS versions);

□ Disabled - Spread Spectrum mode is disabled.

ADVICE

For stable system operation, always turn off Spread Spectrum when overclocking.

Some motherboard models have several independent parameters that control the Spread Spectrum mode for individual system components, for example, CPU Spread Spectrum, SATA Spread Spectrum, PCIE Spread Spectrum, etc.

Preparing for overclocking

Be sure to take a few important steps before overclocking.

□ Check the stability of the system in normal mode. There is no point in overclocking a computer that is normally prone to crashes or freezes, as overclocking will only exacerbate this situation.

□ Find all the necessary BIOS parameters that will be needed during overclocking, and understand their purpose. These parameters were described above, but for different models of boards they may differ, and to take into account the peculiarities of a particular board, you need to study the instructions for it.

□ Understand the BIOS reset method for your board model (see Chapter 5). It is necessary to reset BIOS settings with unsuccessful overclocking.

□ Check the operating temperatures of the main components and their cooling. To control temperatures, you can use the diagnostic utilities from the CD to the motherboard or third-party programs: EVEREST, SpeedFan (www.almico.com), etc. measures to improve cooling of the chipset, video adapter and RAM.

Overclocking processors Intel Core 2

The Intel Core 2 processor family is one of the most successful in the history of the computer industry due to its high performance, low heat generation and excellent overclocking potential. Since 2006 Intel released dozens of models of processors of this family under various brands: Core 2 Duo, Core 2 Quad, Pentium Dual-Core and even Celeron.

For overclocking Core processors 2, you need to increase the FSB frequency, the nominal value of which can be 200, 266, 333 or 400 MHz. You can find out the exact FSB frequency in the specification for your processor, but do not forget that the FSB frequency is indicated taking into account four times the data transfer rate. For example, for a Core 2 Duo E6550 2.33 GHz processor (1333 MHz FSB), the actual FSB frequency is 1333: 4 = 333 MHz.

Increasing the FSB frequency will automatically increase the operating frequency of the RAM, chipset, PCI / PCIE buses and other components. Therefore, before overclocking, you should forcibly reduce them to find out the maximum operating frequency of the processor. Once it is known, you can select the optimal operating frequencies for other components.

The overclocking sequence can be as follows.

1. Set the BIOS to the best settings for your system. Select Disabled (Off) for Spread Spectrum, which is not very overclocking compatible. You may have several such parameters: for a processor (CPU), PCI Express bus, SATA interface and etc.

2. Disable Intel SpeedStep and C1E Support energy saving technologies while overclocking. After completing all experiments, you can re-enable these features to reduce processor power consumption.

3. Manually set the PCI / PCIE bus frequencies. For the PCI bus, you should set the frequency to 33 MHz, and for PCI Express, it is better to set the value in the range of 100-110 MHz. In some models of boards, the Auto value or the nameplate value of 100 MHz may result in worse results than the non-standard value of 101 MHz.

4. Reduce the frequency of the RAM. Depending on the board model, this can be done in one of two ways:

■ set the minimum value of the frequency of the RAM using the Memory Frequency parameter or the like (to access this parameter, you may need to disable automatic memory tuning);

■ set the minimum value of the multiplier that determines the ratio of the FSB frequency to memory using the FSB / Memory Ratio parameter, System Memory Multiplier or similar.

Since the methods for changing the memory frequency differ in different boards, it is recommended to restart the computer and use the diagnostic utilities EVEREST or CPU-Z to verify that the memory frequency has actually decreased.

5. After the preparatory steps, you can proceed directly to the overclocking procedure. To begin with, you can raise the FSB frequency by 20-25% (for example, from 200 to 250 MHz or from 266 to 320 MHz), then try to load the operating system and check its operation. The parameter for setting can be called CPU FSB Clock, CPU Overclock in MHz or something else.

NOTE

To gain access to manual FSB adjustment, you may need to disable automatic installation processor frequency (parameter CPU Host Clock Control) or dynamic overclocking of the motherboard. For example, in system ASUS boards set AI Overclocking (AI Tuning) to Manual.

6. Using the CPU-Z utility, check the real operating frequencies of the processor and memory to make sure you are doing the right thing (Fig. 6.3). Be sure to monitor operating temperatures and voltages. Run 1-2 test programs and make sure there are no crashes or freezes.

7. If the test of the overclocked computer passed without failures, you can restart it, increase the FSB frequency by 5 or 10 MHz, and then check the operability again. Continue until the system crashes for the first time.

8. If a failure occurs, you can reduce the FSB frequency to bring the system back to a stable state. But if you want to know the maximum frequency of the processor, you need to increase the core voltage using the CPU VCore Voltage or CPU Voltage parameter. It is necessary to change the supply voltage smoothly and by no more than 0.1-0.2 V (up to 1.4-1.5 V). When testing a computer with an increased processor voltage, you should definitely pay attention to its temperature, which should not exceed 60 ° C. The ultimate goal of this stage of overclocking is to find the maximum FSB frequency at which the processor can operate for a long time without crashing or overheating.

9. Pick up optimal parameters random access memory. At step 4, we decreased its frequency, but as the FSB frequency increased, the memory frequency also increased. The actual value of the memory frequency can be calculated manually or determined using the utilities EVEREST, CPU-Z, etc. EVEREST and the like.

Rice. 6.3. Controlling the real processor frequency in the CPU-Z program

10. After the processor is overclocked and the optimal parameters of the memory bus have been selected, you should comprehensively test the speed of the overclocked computer and the stability of its operation.

Overclocking Intel Core i3 / 5/7 processors

Until 2010, the most popular processors were Intel Core 2, but by this time competing models from AMD almost caught up with them in performance and also sold at lower prices. However, at the end of 2008, Intel developed Core i7 processors with a completely new architecture, but they were produced in small batches and were very expensive. It is only in 2010 that chips with a new architecture are expected to come to the masses. The company plans to release several models for all market segments: Core i7 for performance systems, Core i5 for the mid-market segment and Core i3 for entry-level systems.

The overclocking procedure for Intel Core i3 / 5/7 processors is not very different from overclocking for Core 2 chips, but to get good results, you should take into account the main features of the new architecture: transferring the DDR3 memory controller directly to the processor and replacing the FSB bus with a new QPI serial bus. Similar principles have long been used in AMD processors, however, Intel has done everything very well. high level, and at the time of this book's release, the performance of the Core i7 processors is unmatched by the competition.

To set the operating frequencies of the processor, RAM, memory modules, DDR3 controller, cache memory and QPI bus, the principle of multiplying the base frequency of 133 MHz (BCLK) by certain factors is used. Therefore, the main method of overclocking processors is to increase the base frequency, however, this will automatically increase the frequencies of all other components. As in the case of overclocking Core 2, it is necessary to first lower the RAM multiplier so that after increasing the base frequency, the memory frequency does not become too high. Adjustment of the multipliers for the QPI bus and DDR3 controller may be necessary during extreme overclocking, and in most cases these components will work normally at higher frequencies.

Based on the above, the approximate order of overclocking a system based on Core i3 / 5/7 can be as follows.

1. Set the BIOS to the best settings for your system. Disable Spread Spectrum, Intel SpeedStep and C1E Support Energy Saving Technologies, and Intel Turbo Boost.

2. Set the minimum multiplier for RAM using the System Memory Multiplier or similar. In most boards, the minimum possible is a multiplier of 6, which corresponds to 800 MHz in normal mode. For this purpose, ASUS motherboards use the DRAM Frequency parameter, which should be set to DDR3-800 MHz.

3. After the preparatory steps, you can start raising the base frequency using the BCLK Frequency or similar. You can start with a frequency of 160-170 MHz, and then stepwise increase it by 5-10 MHz. As statistics show, for most processors it is possible to raise the base frequency to 180-220 MHz.

4. When the first failure occurs, you can slightly reduce the base frequency to bring the system back to working order and test it thoroughly for stability. If you want to squeeze the maximum possible out of the processor, you can try increasing the supply voltage by 0.1-0.3 V (up to 1.4-1.5 V), but you should take care of more efficient cooling. In some cases, you can increase the overclocking potential of the system by raising the voltage of the QPI bus and L3 cache (Uncore), RAM, or the processor's phase-locked loop (CPU PLL).

5. After determining the frequency at which the processor can work for a long time without failures and overheating, you can select the optimal parameters of the RAM and other components.

Overclocking AMD Athlon / Phenom processors

In the mid-2000s, AMD produced Athlon 64 processors that were not bad for that time, but the Intel Core 2 processors released in 2006 surpassed them in all respects. The Phenom processors released in 2008 did not manage to catch up with Core 2 in performance, and only in 2009 the Phenom II processors were able to compete with them on equal terms. By this time, however, Intel had a Core i7 ready, and AMD chips were used in entry-level and mid-range systems.

The overclocking potential of AMD processors is slightly lower than that of Intel Core, and depends on the processor model. The memory controller is located directly in the processor, and communication with the chipset is carried out via a special HyperTransport (HT) bus. The operating frequency of the processor, memory and HT bus is determined by multiplying the base frequency (200 MHz) by certain factors.

To overclock AMD processors, the method of increasing the base frequency of the processor is mainly used, while the frequency of the HyperTransport bus and the frequency of the memory bus will automatically increase, so they will need to be reduced before starting overclocking. The company's range also includes models with an unlocked multiplier (Black Edition series), and such chips can be overclocked by increasing the multiplier; in this case, there is no need to adjust the parameters of the RAM and the NT bus.

You can overclock Athlon, Phenom or Sempron processors in the following order.

1. Set the BIOS settings that are optimal for your system. Disable Cool "n" Quiet and Spread Spectrum technologies.

2. Reduce the frequency of the RAM. To do this, you may first have to cancel the setting of memory parameters using SPD (the Memory Timing by SPD parameter or similar), and then specify the lowest possible frequency in the Memory Frequency for parameter or the like (Fig. 6.4).

3. Decrease the frequency of the HyperTransport bus using the HT Frequency parameter or similar (Fig. 6.5) by 1-2 steps. For example, for Athlon 64 processors, the nominal HT frequency is 1000 MHz (multiplier 5) and you can lower it to 600-800 MHz (multiplier 3 or 4). If your system has a parameter for setting the frequency of the memory controller built into the processor, for example, CPU / NB Frequency, it is also recommended to decrease its value.

4. Set fixed frequencies for PCI (33 MHz), PCI Express (100-110 MHz) and AGP (66 MHz) buses.

5. After all the above steps, you can start overclocking itself. To begin with, you can raise the base frequency by 10-20% (for example, from 200 to 240 MHz), then try to load the operating system and check its operation. The parameter to set can be called CPU FSB Clock, CPU Overclock in MHz or similar.

Rice. 6.4. Setting the frequency of the RAM

Rice. 6.5. Reducing the operating frequency of the HyperTransport bus

6.Using the CPU-Z utility, check the actual operating frequencies of the processor and memory. If the test of the overclocked computer passed without failures, you can continue to increase the base frequency by 5-10 MHz.

7. If a failure occurs, you can reduce the base frequency to bring the system back to a stable state, or continue overclocking while increasing the core voltage (Figure 6.6). You need to change the supply voltage smoothly and by no more than 0.2-0.3 V. When testing a computer with an increased processor supply voltage, pay attention to the processor temperature, which should not be higher than 60 ° C.

Rice. 6.6. Increasing the voltage of the processor core

8. After overclocking the processor, set the optimal frequency of the HT bus, RAM and its controller, test the speed and stability of the overclocked computer. To reduce the heating of the processor, turn on the Cool "n" Quiet technology and check the stability of operation in this mode.

Unlocking cores in Phenom ll / Athlon II processors

In the processor family AMD Phenom II, which came out in 2009, are available in various models with two, three and four cores. AMD released dual- and triple-core models by disabling one or two cores in a quad-core processor. This was explained by considerations of economy: if a defect was found in one of the cores of a quad-core processor, it was not thrown away, but the defective core was turned off and sold as a tri-core.

As it turned out later, a locked core can be enabled using the BIOS, and some of the unlocked processors can work fine with all four cores. This phenomenon can be explained by the fact that over time, the number of defects in the production of quad-core processors decreased, and since there was a demand in the market for two- and three-core models, manufacturers could forcibly turn off working cores.

At the time of the book's release, it was known about successful unlocking of most models of this family: Phenom II X3 7xx series, Phenom II X2 5xx series, Athlon II X3 7xx series, Athlon II X3 4xx series and some others. In the four-core Phenom II X4 8xx and Athlon II X4 6xx models, there is a possibility of unlocking the L3 cache, and in the single-core Sempron 140 - the second core. The probability of unlocking depends not only on the model, but also on the batch in which the processor is released. There were games in which it was possible to unlock more than half of the processors, and in some games only rare copies could be unlocked.

To unlock, you need to System BIOS the board had support for Advanced Clock Calibration (ACC) technology. This technology is supported by AMD chipsets with south bridge SB750 or SB710, as well as some NVIDIA chipsets, such as GeForce 8200, GeForce 8300, nForce 720D, nForce 980.

The unlocking procedure itself is simple, you just need to set the Auto value for the Advanced Clock Calibration parameter or similar. Some MSI boards should also enable the Unlock CPU Core option. In case of failure, you can try to adjust the ACC manually by experimentally choosing the value of the Value parameter. Sometimes, after turning on ACC, the system may not boot at all, and you will have to clear the CMOS content using a jumper (see Chapter 5). If you failed to unlock the processor by any means, turn off the ACC, and the processor will work normally.

You can check the parameters of the unlocked processor using the diagnostic utilities EVEREST or CPU-Z, but to be sure of a positive result finally, you should conduct a comprehensive test of the computer. Unlocking is done on the motherboard and does not change the physical state of the processor. You can cancel unlocking at any time by disabling ACC, and when you install an unlocked processor on another board, it will be locked again.

Attention! This article is about the PCI bus and its PCI64 and PCI-X derivatives! Do not confuse it with the newer bus (PCI Express), which is completely incompatible with the tires described in this FAQ.

PCI 2.1- differed from 2.0 by the possibility of simultaneous operation of several bus-master devices (so-called. competitive regime), as well as the appearance universal cards extensions capable of operating in both 5V and 3.3V slots. The ability to work with 3.3V cards and the presence of appropriate power lines in version 2.1 was optional. PCI66 and PCI64 extensions appeared.

PCI 2.2- a version of the basic bus standard that allows the connection of expansion cards with a signal voltage of both 5V and 3.3V. 32-bit versions of these standards were the most common slot type at the time of writing this FAQ. The slots used are 32-bit, 5V.
Expansion cards made in accordance with these standards have a universal connector and are able to work in almost all later varieties of PCI bus slots, as well as, in some cases, in 2.1 slots.

PCI 2.3- The next version of the common PCI bus standard, expansion slots conforming to this standard are not compatible with PCI 5V cards, despite the continued use of 32-bit slots with a 5V key. Expansion cards have a universal connector, but cannot work in 5V slots early versions(up to 2.1 inclusive).
We remind you that the supply voltage (not signal!) 5V is preserved absolutely on all versions of PCI bus connectors.

PCI 64- an extension to the basic PCI standard, introduced in version 2.1, doubling the number of data lines, and therefore the bandwidth. The PCI64 slot is an extended version of a regular PCI slot. Formally, the compatibility of 32-bit cards with 64-bit slots (subject to the availability of the total supported signal voltage) is complete, and the compatibility of a 64-bit card with 32-bit slots is limited (in any case, performance will be lost), exact data in each case can be found in the specifications of the device.
The first PCI64 versions (derived from PCI 2.1) used a 5V 64-bit PCI slot and ran at 33MHz.

PCI 66- The PCI expansion that appeared in version 2.1 with support for a 66MHz clock frequency, as well as PCI64, allows you to double the bandwidth. Starting from version 2.2, it uses 3.3V slots (32-bit version is practically not found on PCs), cards have either a universal or 3.3V form factor. (There were also solutions based on version 2.1, casuistically rare on the PC market 5V 66 MHz, such slots and cards were only compatible with each other)

PCI 64/66- a combination of the above two technologies, allows you to quadruple the data transfer rate compared to the basic PCI standard, and uses 64-bit 3.3V slots, compatible only with general-purpose and 3.3V 32-bit expansion cards. PCI64 / 66 standard cards have a universal (with limited compatibility with 32-bit slots) or 3.3V form factor (the latter option is fundamentally incompatible with 32-bit 33MHz slots of popular standards)
Currently, the term PCI64 means PCI64 / 66, since 33MHz 5V 64-bit slots have not been used for a long time.

PCI-X 1.0- Expansion PCI64 with the addition of two new operating frequencies, 100 and 133 MHz, as well as a mechanism for separate transactions to improve performance when multiple devices work at the same time. Generally backward compatible with all 3.3V and general purpose PCI cards.
PCI-X cards usually run in 64-bit 3.3V format and have limited backward compatibility with PCI64 / 66 slots, and some PCI-X cards are in a universal format and are able to work (although this has almost no practical value) in regular PCI 2.2 /2.3.
In difficult cases, in order to be completely sure of the performance of your chosen combination of motherboard and expansion card, in case you need to look at the compatibility lists of the manufacturers of both devices.

PCI-X 2.0- further expansion of PCI-X 1.0 capabilities, added speeds at 266 and 533 MHz, as well as parity error correction during data transmission (ECC). Allows splitting into 4 independent 16-bit buses, which is used exclusively in embedded and industrial systems, the signal voltage is reduced to 1.5V, but the connectors are backward compatible with all cards using the 3.3V signal voltage.

PCI-X 1066 / PCI-X 2133- projected future versions of the PCI-X bus, with the resulting operating frequencies of 1066 and 2133 MHz, respectively, originally intended for connecting 10 and 40 Gbit Ethernet adapters.

For all PCI-X bus variants, there are the following restrictions on the number of devices connected to each bus:
66MHz - 4
100MHz - 2
133MHz - 1 (2, if one or both devices are not on expansion cards, but are already integrated on one card together with the controller)
266.533MHz and above -1.

That is why, in some situations, to ensure the stability of the operation of several installed devices it is necessary to limit the maximum operating frequency of the used PCI-X bus (this is usually done with jumpers)

CompactPCI- a standard for connectors and expansion cards used in industrial and embedded computers. Not mechanically compatible with any of the "generic" standards.

MiniPCI- standard for boards and connectors for integration into laptops (usually used for adapters wireless network) and directly to the surface. Also, it is not mechanically compatible with anything other than itself.

Types of PCI expansion cards:

Summary table of constructs of cards and slots, depending on the version of the standard:

Summary table of compatibility of cards and slots, depending on the version and construct:

Practical overclocking

CPU overclocking methods

There are two methods of overclocking: increasing the system bus (FSB) frequency and increasing the multiplier (multiplier). At the moment, the second method cannot be applied on almost all serial AMD processors. Exceptions to the rule are: Athlon XP processors (Thoroughbred, Barton, Thorton ) / Duron (Applebred), released before week 39 of 2003, Athlon MP, Sempron (socket754; downgrade only), Athlon 64 (downgrade only), Athlon 64 FX53 / 55. In serial Intel processors, the multiplier is also completely locked. by increasing the multiplier, it is the most "painless" and simplest, since only the processor clock frequency increases, and the frequencies of the memory bus, AGP / PCI buses remain nominal, therefore, determine the maximum clock frequency of the processor at which it can work correctly using this method especially simple. It is a pity that now it is quite difficult, if not impossible, to find AthlonXP processors with an unlocked multiplier on sale. Overclocking the processor by increasing the FSB has its own peculiarities. For example, as the FSB frequency increases, the memory bus frequency and the AGP / PCI bus frequency increase. Special attention should be paid to the PCI / AGP bus frequencies, which in most chipsets are related to the FSB frequency (does not apply to nForce2, nForce3 250). This dependence can be circumvented only if the BIOS of your motherboard has the appropriate parameters - the so-called dividers responsible for the PCI / AGP to FSB ratio. You can calculate the divider you need using the FSB / 33 formula, i.e., if the FSB frequency = 133 MHz, then 133 should be divided by 33, and you will get the divider you need - in this case this is 4. The nominal frequency for the PCI bus is 33 MHz, and the maximum frequency is 38-40 MHz, it is not recommended to set it higher, to put it mildly, as this can lead to the destruction of PCI devices. By default, the memory bus frequency rises synchronously with the FSB frequency, so if the memory does not have enough overclocking potential, it can play a limiting role. If it is obvious that the frequency of the RAM has reached its limit, you can do the following:

• Increase memory timings (for example, change 2.5-3-3-5 to 2.5-4-4-7 - this can help you squeeze a few more MHz out of the RAM).
• Increase the voltage on the memory modules.
• Overclock CPU and memory asynchronously.

Reading is the mother of learning

First, you need to study the instructions for your motherboard: find the sections BIOS menu responsible for FSB, RAM, memory timings, multiplier, voltages, PCI / AGP frequency dividers. If the BIOS does not have any of the above parameters, then overclocking can be done using jumpers (jumpers) on the motherboard. You can find the purpose of each jumper in the same manual, but usually the board itself contains information about the function of each. It happens that the manufacturer himself deliberately hides the "advanced" BIOS settings - to unlock them, you need to press a certain key combination (this is often found in motherboards manufactured by Gigabyte). I repeat: all the necessary information can be found in the instructions or on the official website of the motherboard manufacturer.

Practice

We go into the BIOS (usually to enter, you need to press the Del key at the time of recalculating the amount of RAM (i.e., when the first data appears on the screen after restarting / turning on the computer, press the Del key), but there are models of motherboards with a different key for entering the BIOS - for example, F2), we are looking for a menu in which you can change the frequency of the system bus, memory bus and manage timings (usually these parameters are located in one place). I think that overclocking the processor by increasing the multiplier will not cause any difficulties, so let's go straight to raising the system bus frequency. Raise the FSB frequency (by about 5-10% of the nominal), then save the changes, reboot and wait. If everything is fine, the system starts with a new FSB value and, as a consequence, with a higher clock speed of the processor (and memory, if you overclock them synchronously). Booting Windows without any excesses means that half the battle is already done. Next, run the CPU-Z program (at the time of this writing, its latest version was 1.24) or Everest and make sure that the processor clock speed has increased. Now we need to check the processor for stability - I think everyone has a 3DMark 2001/2003 distribution on their hard drives - although they are designed to detect the speed of a video card, but for a superficial check of system stability, you can "drive" them too. For a more serious test, you need to use Prime95, CPU Burn-in 1.01, S&M (in more detail about the tester programs below). If the system has passed the test and behaves stably, we reboot and start all over again: go to the BIOS again, increase the FSB frequency, save the changes and test the system again. If during testing you are "thrown out" of the program, the system freezes or reboots, you should "roll back" a step back - to the processor frequency when the system was stable - and conduct more extensive testing to make sure that the work is completely stable. Do not forget to monitor the temperature of the processor and the frequencies of the PCI / AGP buses (in the OS, the PCI frequency and temperature can be viewed using the Everest program or proprietary programs of the motherboard manufacturer).

Voltage rise

It is not recommended to increase the voltage on the processor by more than 15-20%, but it is better that it varied within 5-15%. There is a sense in this: the stability of work increases and new horizons for overclocking open up. But be careful: as the voltage rises, the power consumption and heat dissipation of the processor increases and, as a result, the load on the power supply increases and the temperature rises. Most motherboards allow you to set the voltage on the RAM to 2.8-3.0 V, the safe limit is 2.9 V (to further increase the voltage, you need to make a voltmod of the motherboard). The main thing when the voltage rises (not only in the RAM) is to control the heat release, and, if it has increased, to organize the cooling of the overclocked component. One of better ways Determining the temperature of any component of the computer is the touch of your hand. If you cannot touch the component without pain from the burn, it needs urgent cooling! If the component is hot, but you can hold your hand, then cooling it would not hurt. And only if you feel that the component is barely warm or even cold, then everything is fine, and it does not need cooling.

Timings and frequency dividers

Timings are delays between individual operations performed by the controller when accessing memory. There are six of them: RAS-to-CAS Delay (RCD), CAS Latency (CL), RAS Precharge (RP), Precharge Delay or Active Precharge Delay (often referred to as Tras), SDRAM Idle Timer or SDRAM Idle Cycle Limit, Burst Length ... Describing the meaning of each is a pointless business and no one needs it. It's better to find out right away which is better: small timings or high frequency... There is an opinion that timings are more important for Intel processors, while for AMD - frequency. But do not forget that for AMD processors, the memory frequency achieved in synchronous mode is most often important. For different processors, different memory frequencies are "native". For Intel processors, the following frequency combinations are considered "own": 100: 133, 133: 166, 200: 200. For AMD on nForce chipsets, synchronous operation of FSB and RAM is better, and asynchrony has little effect on AMD + VIA. On systems with an AMD processor, the memory frequency is set in the following percentages with FSB: 50%, 60%, 66%, 75%, 80%, 83%, 100%, 120%, 125%, 133%, 150%, 166% , 200% are the same divisors, but presented in a slightly different way. And on systems with Intel processor dividers look more familiar: 1: 1, 4: 3, 5: 4, etc.

Black screen

Yes, it also happens :) - for example, when overclocking: you just set such a clock speed of the processor or RAM (perhaps you specified too low memory timings) that the computer cannot start - or rather, it starts, but the screen remains black, and the system does not show any "signs of life". What to do in this case?

• Many manufacturers build in their motherboards a system of automatic reset of parameters to nominal. And after such an "incident" with an overestimated frequency or low timings this system must do its "dirty" job, but this does not always happen, so you need to be ready to work with pens.
• After turning on the computer, press and hold the Ins key, after which it should start successfully, and you must enter the BIOS and set the operating parameters of the computer.
• If the second method does not help you, you need to turn off the computer, open the case, find on the motherboard a jumper responsible for resetting BIOS settings - the so-called CMOS (usually located near the BIOS chip) - and set it to Clear CMOS mode for 2-3 seconds, and then return to the nominal position.
• There are motherboard models without a jumper for resetting BIOS settings (the manufacturer relies on its automatic system reset BIOS settings) - then you need to remove the battery for a while, which depends on the manufacturer and model of the motherboard (I conducted such an experiment on my Epox EP-8RDA3G: I took out the battery, waited 5 minutes, and the BIOS settings were reset).

Information programs and utilities

CPU-Z is one of best programs that provide basic information about the processor, motherboard, and RAM installed in your computer. The program interface is simple and intuitive: there is nothing superfluous, and all the most important is in plain sight. The program supports the latest innovations from the world of "hardware" and is periodically updated. The latest version at the time of this writing is 1.24. Size - 260 Kb. You can download the program at cpuid.com.

Everest Home / Professional Edition (formerly AIDA32) is an information and diagnostic utility with more advanced functions for viewing information about the installed hardware, operating system, DirectX, etc. The differences between the home and professional versions are as follows: the Pro version does not have a RAM test module (read / write), it also lacks a rather interesting Overclock subsection, which contains basic information about the processor, motherboard, RAM, processor temperature, motherboard. motherboard and hard drive, as well as overclocking your processor in percentage :). The Home version does not include software accounting, advanced reports, interaction with databases, remote control, enterprise-level functions. In general, these are all the differences. I myself use the Home-version of the utility, because additional features I don't need Pro versions. I almost forgot to mention that Everest allows you to view the PCI bus frequency - to do this, you need to expand the Motherboard section, click on the subsection with the same name and find the Chipset bus properties / Real frequency item. The latest version at the time of this writing is 1.51. The home version is free and weighs 3 Mb, the Pro version is paid and takes 3.1 Mb. You can download the utility at lavalys.com.

Stability testing

The name of the CPU Burn-in program speaks for itself: the program is designed to "warm up" the processor and check its stable operation. In the main window of CPU Burn-in, you need to specify the duration, and in the options - select one of two testing modes:

• testing with enabled error checking (Enable error checking);
• testing with disabled error checking, but with maximum processor "heating" (Disable error checking, maximum heat generation).

When you enable the first option, the program will check the correctness of processor calculations, and the second will allow you to "warm up" the processor almost to temperatures close to the maximum. CPU Burn-in weighs about 7 Kb.

The next decent benchmark for CPU and RAM is Prime95. Its main advantage is that when an error is detected, the program does not spontaneously "hang up", but displays data on the error and the time of its detection on the working field. Opening the Options -> Torture Test… menu, you can independently choose from three testing modes or specify your own parameters. For more efficient detection of processor and memory errors, it is best to set the third test mode (Blend: test some of everything, lots of RAM tested). Prime95 weighs 1.01 Mb and can be downloaded from mersenne.org.

The S&M program was released relatively recently. At first, it was conceived to test the stability of the processor's power converter, then the RAM test and support for Pentium 4 processors with HyperThreading technology were implemented. Presently latest version S&M 1.0.0 (159) is supported by more than 32 (!) Processors and there is a check of the stability of the processor and RAM, in addition, S&M has a flexible system of settings. Summarizing all of the above, it can be argued that S&M is one of the best programs of its kind, if not the best. The program interface has been translated into Russian, so it is rather difficult to get confused in the menu. S&M 1.0.0 (159) weighs 188 Kb, you can download it at testmem.nm.ru.

The aforementioned tester programs are designed to test the processor and RAM for stability and identify errors in their work, they are all free. Each of them loads the processor and memory almost completely, but I want to remind you that programs used in everyday work and not intended for testing can rarely load the processor and RAM so much, so we can say that testing occurs with a certain margin.

The author does not accept any responsibility for the breakdown of any hardware your computer, as well as for crashes and "glitches" in the work of any software installed on your computer.

In this article, we will discuss the reasons for the success of the PCI bus and describe the high-performance technology that is replacing it - the PCI Express bus. We will also consider the history of development, hardware and software levels of the PCI Express bus, features of its implementation and list its advantages.

When in the early 1990s. she appeared, then by her own technical specifications significantly surpassed all buses that existed until that time, such as ISA, EISA, MCA and VL-bus. At that time, the PCI (Peripheral Component Interconnect) bus, which ran at 33 MHz, was well suited for most peripheral devices... But today the situation has changed in many ways. First of all, the clock speeds of the processor and memory have increased significantly. For example, processor clock speeds have increased from 33 MHz to several GHz, while operating frequency PCI has increased to only 66 MHz. The emergence of technologies such as Gigabit Ethernet and IEEE 1394B threatened throughput PCI bus can be spent on servicing a single device based on these technologies.

At the same time, the PCI architecture has a number of advantages over its predecessors, so it was irrational to completely revise it. First of all, it does not depend on the type of processor, it supports buffer isolation, bus mastering technology and PnP technology in full. Buffer isolation means that the PCI bus operates independently of the internal processor bus, which allows the processor bus to function independently of the speed and load of the system bus. With bus capture technology, peripherals can directly control the transfer of data over the bus, instead of waiting for help from the CPU, which would affect system performance. Finally, Plug and Play support allows for automatic configuration and configuration of devices using it and avoids the hassle of jumpers and switches, which pretty much ruined the lives of owners of ISA devices.

Despite the undoubted success of PCI, it faces serious problems at the present time. These include limited bandwidth, lack of real-time data transfer features, and lack of support. network technologies new generation.

Comparative characteristics of various PCI standards

It should be noted that the actual throughput may be less than the theoretical one due to the principle of the protocol and the peculiarities of the bus topology. In addition, the total bandwidth is shared among all devices connected to it, so the more devices sit on the bus, the less bandwidth each of them gets.

Improvements to the standard such as PCI-X and AGP were designed to eliminate its main drawback - low clock speed. However, an increase in the clock frequency in these implementations entailed a decrease in the effective bus length and the number of connectors.

The new generation of the bus - PCI Express (or PCI-E for short), was first introduced in 2004 and was intended to solve all the problems that its predecessor faced. Most new computers today are equipped with PCI Express. Although standard PCI slots are also present in them, the time is not far off when the bus will become the property of history.

PCI Express architecture

The bus architecture has a layered structure as shown in the figure.

The bus supports the PCI addressing model, which allows all currently existing drivers and applications to work with it. In addition, the PCI Express bus uses the standard PnP mechanism provided by the previous standard.

Consider the purpose of the various levels of PCI-E organization. At the program level of the bus, read / write requests are formed, which are transmitted at the transport level using a special packet protocol. The data layer is responsible for error-correcting coding and ensures data integrity. The basic hardware layer consists of a dual simplex channel made up of a transmit and receive pair, collectively referred to as a link. The total bus speed of 2.5 Gb / s means that the bandwidth for each PCI Express lane is 250 Mb / s in each direction. Taking into account the loss of protocol overhead, about 200 Mb / s is available for each device. This bandwidth is 2-4 times higher than what was available for PCI devices. And, unlike PCI, if the bandwidth is distributed among all devices, then it goes to each device in full.

Today there are several versions of the PCI Express standard, differing in their bandwidth.

PCI Express x16 bus bandwidth for different versions PCI-E, Gb / s:

• 32/64
• 64/128
• 128/256

PCI-E bus formats

At the moment, various options for PCI Express formats are available, depending on the purpose of the platform - a desktop computer, laptop or server. Servers that require more bandwidth have more PCI-E slots, and these slots have more trunks. In contrast, laptops can only have one line for mid-speed devices.

PCI Express x16 graphics card.

PCI Express Expansion Cards are very similar to PCI cards, but PCI-E slots have increased grip to ensure that the card does not slip out of the slot due to vibration or during shipping. There are several form factors of PCI Express slots, the size of which depends on the number of lanes used. For example, a bus with 16 lanes is designated PCI Express x16. Although the total number of lanes can be as high as 32, in practice most motherboards are now equipped with PCI Express x16.

Smaller form factors can be plugged into larger slots without compromising performance. For example, a PCI Express x1 card can be plugged into a PCI Express x16 slot. As with the PCI bus, you can use a PCI Express extension cable to connect devices if necessary.

Connector appearance different types on the motherboard. From top to bottom: PCI-X slot, PCI Express x8 slot, PCI slot, PCI Express x16 slot.

Express Card

The Express Card standard offers a very simple way to add hardware to a system. The target market for Express Card modules is laptops and small PCs. Unlike traditional desktop expansion cards, the Express card can be plugged into the system at any time while the computer is running.

One of the popular Express Cards is the PCI Express Mini Card, designed as a replacement for Mini PCI cards. A card created in this format supports both PCI Express and USB 2.0. PCI dimensions Express Mini Card is 30x56mm. PCI Express Mini Card can connect to PCI Express x1.

Benefits of PCI-E

PCI Express technology has provided an advantage over PCI in the following five areas:

1. More high performance... With just one lane, PCI Express has twice the bandwidth of PCI. In this case, the bandwidth increases in proportion to the number of lines in the bus, maximum amount which can reach 32. An additional advantage is that information on the bus can be transmitted simultaneously in both directions.
2. Simplification of I / O. PCI Express takes advantage of buses such as AGP and PCI-X while offering less complex architecture and comparative ease of implementation.
3. Layered architecture. PCI Express offers an architecture that can accommodate new technologies and does not require significant software upgrades.
4. Next-generation I / O technologies. PCI Express provides new opportunities for data acquisition using concurrent data transfer technology that ensures timely information is received.
5. Ease of use. PCI-E makes it much easier for the user to upgrade and expand the system. Additional Express card formats, such as ExpressCard, dramatically increase the ability to add high-speed peripherals to servers and laptops.

Conclusion

PCI Express is a peripheral bus technology that replaces technologies such as ISA, AGP and PCI. Its use significantly increases the performance of the computer, as well as the user's ability to expand and update the system.