Lowering the Memory Frequency
Let’s find the corresponding BIOS option that is responsible for the memory working frequency. It can sit in various sections of the BIOS and be called differently, that is why you should better consult the mainboard manual first. This option is most often found in one of the two sections: the page devoted to memory overclocking and timing settings, or the page dealing with CPU overclocking. The first page is most likely to be called Advanced Chipset Features or simply Advanced , like by ASUS. The option we are looking for is called Memclock index value and is measured in megahertz:
It can also be located in the page called POWER BIOS Features like by EPoX and be called System Memory Frequency or simply Memory Frequency . The frequency in this case might be marked as DDR400, DDR333 or DDR266, and might be just PC133 or PC100.
It doesn’t really matter for us: all we need to do is to find this parameter and set the minimal possible value for it. There are several ways to set this value depending on the BIOS version and the mainboard manufacturer. You can either press <Enter> and select the value from the drop-down list with the keyboard arrow keys, or you can sometimes go through the values with the PageUp, PageDown, “+” or “-“ keys.
Why do we have to set the memory frequency to the minimum? I bet your memory is far not that slow and can work a way better than the minimum value we set for it. Well, during the CPU overclocking we will increase the FSB frequency. In this case the memory frequency will also grow up, however, we hope that if it starts growing up from the minimal value instead of the nominal one, it will have more room to grow. Namely, it is more likely to stay within the supported range and not to limit the CPU overclocking process. Just to make sure, you can also set the memory timings to slightly higher values than those set by default.
Firstly, it will push farther back the stability limits for our system memory. Secondly, if the timings are set automatically, the mainboard may set memory timings to extremely low non-functional values, and by doing it manually we can always make sure that the memory timings will work just fine. To see if it worked, we have to save the BIOS changes and reboot the system. To do this you have to select Save & Exit Setup option or just hit F10 key and confirm your intentions by pressing <Enter> or “Y” (Yes) in the older BIOS versions.
In most cases it is enough to set the memory working frequency to the minimum, so you can finally get down to the actual CPU overclocking. However, since we are doing it for the first time let’s not rush the things and double-check that everything has been done the right way.