Hi My computer has a PCChips M925LR mobo with Intel Pentium 4 CPU (1.8 GHz) and VIA VT8751 Apollo P4M266 (North)/VIA VT8233C (South) chipset. Jumpers are available to change the CPU frequency from 100MHz to 133MHz. However, when I tried this, the computer just would not boot. So, I had to replace the jumpers to the 100MHz configuration. However, it just doesn't make sense to me that this instruction which is clearly explained and detailed in the mobo manual doesn't actually work for my mobo. Anybody know if I'm overlooking something here? TIA Paul

Since it does boot when set to 100Mhz and does not boot when set to 133Mhz, then I'm guessing that your CPU is for a 100Mhz system. Or are you trying to get the MOBO to work with a 133Mhz CPU? Michael J

It also could be that your memory will not work reliably at 133mhz. Sorry, I do not check for private messages

Hi MichaelJ Thanks for your reply. Just to explain that I have been working with/on this computer for the last month as I am temporarily away from home. So my knowledge of it is less than complete. You are correct in suggesting that the CPU currently works at 100MHz (multiplier is 18 to give 1800 MHz). However, I had understood that I should still be able to increase the frequency to 133MHz to induce a higher FSB speed which will benefit RAM memory performance. In addition, I could reduce the CPU multiplier (for example to 14) to avoid the CPU being overclocked (at least, not excessively). It looks from what you are saying that, to get the CPU speed up, I need a different CPU. Is this the only option? Thanks again Paul

Hi Ham30 Thanks for your reply. I have two sticks of RAM which are 128MB PC133 SDRAM. Doesn't the 133 indicate that the sticks are designed for operation at 133MHz? Or is there some more subtle meaning behind this designation? Paul

IF your P4 is supposed to run at 100MHz (400FSB), changing the jumper to 133MHz (533FSB) means you're attempting to overclock it. Your CPU speed would increase to 2.4GHz (18 x 133MHz). You *may* be able to accomplish this if you increase the CPU voltage (vcore), but there's no guarantee

pc133 ram means it is designed to run at up to 133mhz. Some CPUs will work when overclocked, some will not. It does not just depend on the model, even CPUs of same model respond differently to overclocking attempts. It's probably just because your CPU cant take the increased FSB - which is above its design intention so you cant complain. If you get it working by upping the voltage you will probably need addtnl cooling as it will get hotter than before and potentially be unstable - crashing more often, and you might just destroy it by pushing it too far. Unless you can afford to lose a CPU and buy a new one, it's not worth risking.