How to Overclock Your Locked 32-bit CPU
Most people run 32-bit systems today. If you’re one of those, and your CPU is INTEL then most probably it will be “locked” unless it’s an “Extreme” chip (denoted by the letter “X” in its model number). When a CPU is locked, this means that its multiplier value cannot be set above a certain value. As you may already know:
CPUclock = FSB * CPUmultiplier
The FSB is the Front Side Bus clock provided by the motherboard. If the CPU multiplier is fixed below a certain value, then in order to increase the CPU clock we have to increase the FSB, which will have many effects on the motherboard and memory settings that we’ll have to adjust.
Before you start to change your BIOS settings, you have to make sure you can “reset you BIOS” to the default settings. This is important because your system might be unstable or the operating system might refuse to start. In such case you’ll need to reset the BIOS so your system is stable again.
The procedure goes as follows:
1- Set your memory timings in your BIOS. The lower the memory timings the faster they are. Refer to the manufacture’s specs for getting the best values. Don’t worry if you’re not sure if they’re good as you’ll get a chance to modify them later.
2- Increase your FSB clock speed a little bit. Leave the Vcore and other voltage settings at their default – these are the voltages that operate the system and we want them minimized. The “default” settings are generally an over-estimate but we’ll take care of them later.
3- Test the system with an application that uses memory extensively. If your system runs stable for sufficient time you can go to your BIOS and increase the FSB a bit more and retest. If you’re satisfied with the results then go to step 5.
4- If the system becomes unstable when testing, try increasing Vcore and Vdimm by one level (maybe 0.05v) and retest. You can continue increasing the voltages or lowering the FSB until you get satisfying results. Be careful though that increasing Vcore higher that 15{70c334fb92e874d1e6848b98072ad90d8e1e4d18d72219bf8863dcf279bcb8a9} than the rated value may damage your chip.
5- You can now re-adjust the memory timings to get better memory performance.
6- You might want to adjust your memory divider. When choosing a memory divider value, the memory will be operating in “asynchronous mode”. Running asynchronously may require adjusting the memory voltages manually to make it stable.
7- When you are satisfied with what you reached so far, try now to lower the voltages’ values. We want to minimize voltages to minimize temperature.
Note that there is a limit for overclocking the memory. You must have a memory that can work with the high FSB speeds you choose. Sometimes you might have to buy another memory. In such case, it’s up to you to decide if the performance gain is worth the additional costs of a new memory.
You can follow other mechanisms, as long as you keep your system stable and always observe the temperature. The temperature increases linearly with the FSB and exponentially with the voltage. That’s why we don’t just set all voltages to their maximum to support max clock speeds. If you have to increase your voltages and you noticed a massive increase in the system temperature, you can purchase additional cooling devices. You can test your system performance and temperature in detail using some software tools like SiSoft Sandra, Memtest86+ and Prime95. Give a lot of time to testing for long times to make sure your system is stable with your new settings and is working at the speed you were wishing for.
