Getting Ready to Overclock

Before you begin to overclock your CPU, you should do some preparatory work. Check for BIOS updates on your mainboard manufacturer’s website and read through the list of changes. There have been numerous occasions when a mainboard with poor overclockability would transform miraculously after a BIOS update. New BIOS versions not only correct errors, but sometimes add new parameters or expand the range of the available ones. You can read the version number of your current BIOS during the startup. If the information disappears too quickly, press the Pause key on your keyboard. Sometimes the version number is shown in BIOS Setup. You can also learn it from informational utilities or special-purpose BIOS updaters. You don’t have to write every BIOS version, from the oldest to the newest, into your mainboard. The freshest version includes everything from the earlier ones. And even if the latest version is not the most optimal for overclocking, it is at least sure to be free from the errors of the earlier versions.

So, you are in your mainboard’s BIOS and want to know what to do next? Perhaps you’ve got an “intelligent?mainboard that can do everything by itself, and you only have to specify the desired level of CPU overclocking or the FSB frequency. However, it’s better to take care of everything by yourself to avoid any problems. This will save your time and components and will ensure the best possible result.

You should reduce the memory frequency first. As I said above, everything is interrelated in the PC, so when you are overclocking and increasing the FSB frequency, the memory frequency increases proportionally. And if the memory works at a high frequency by default, it may become the limit to further CPU overclocking. It’s desirable to set the minimum possible memory frequency in the BIOS. Don’t worry about the performance reduction. You’ll increase it back through overclocking. Moreover, you can return to the memory after you’ve found the maximum frequency of your CPU and try to increase it speed back again.

Next you should set higher memory timings, at least the basic ones, for example 5-5-5-15-2T for the widespread DDR2 memory type. You should do this for the same reason as you reduced the memory frequency, i.e. to prevent the memory chips from interfering with the CPU overclocking. Memory can work at a high frequency with high timings or at a low frequency with low timings. Sometimes two or more combinations of possible settings are written into the memory module’s SPD chip. The reduction of frequency can be taken as a permission to reduce the timings if the latter are set up by the mainboard automatically. This combination of a low frequency and low timings may be quite normal for the default operating mode of the CPU, but low timings may become a problem when the memory frequency has increased due to your overclocking attempts.

If BIOS parameters are set at Auto, the mainboard can control them automatically. Mainboards control their parameters normally most of the time, but not always. That’s why you should avoid this and specify parameter values explicitly.

For example, you may want to fix the CPU multiplier at its default value. I know of cases when an intelligent mainboard’s BIOS reduced the multiplier at startup. Perhaps it was an error, but anyway.

Moreover, you may also want to explicitly specify the voltages so that the mainboard didn’t increase them at overclocking. The memory voltage should, on the contrary, be increased a little to make the memory chips stable. By the way, it’s sometimes not easy to learn the default voltage values. Many mainboards show the CPU voltage in a special information line. Sometimes the default voltage is the minimum possible one. The CPU voltage can also be read with a special program like CoreTemp or RM Clock.

You can also try to determine the voltage by a guess method. The mainboard normally selects the default CPU voltage, and you should view it with some monitoring utility or in the PC Health section of the BIOS. Then specify a voltage value explicitly, trying to guess it so that it coincided with the value measured when it was set automatically.

The Spread Spectrum feature should be disabled unless the mainboard disables it automatically when overclocking. This option is meant to minimize electromagnetic interference the operating computer generates but it may limit your system’s overclockability.

Some mainboards are able to overclock the graphics card in automatic mode. If the graphics card is under heavy load, its frequencies are increased a little. You should disable this feature. You can’t get a big performance increase this way, but problems are quite possible.