What's the relationship between FSB of the CPU, clock speed of the m/b, and the multiplier? I understand how the clock speed times the multiplier equals the CPU speed, and have played with increasing the clock speed using jumpers to add on those Mhz.

I think ( ) the clock speed of the m/b is also the Mhz that the RAM etc is run on?

I currently have a Socket A Duron 700Mhz running at 100Mhz x 7. My m/b allows clock speeds of up to 115Mhz using jumpers. How does all this relate to the FSB? (I think this CPU has an FSB of 200Mhz??). The m/b says it supports over 1Ghz CPUs, so would it be upgradable with the Athlon Socket A 1Ghz+ CPUs? I think these have a 266FSB? Or would I need to acheive a higher clock speed from my motherboard?

Thinking about it now...it may be coincidense but it seems that the FSB is double the clock speed of the motherboard. That would figure, as 100Mhz x 2 = 200Mhz. (My current setup), and the Athlons 266Mhz would calulate to 133Mhz clock speed, which is a nice round number...

Well, thanks for any help you may be able to give.

Hi,

Basically the FSB (Front Side Bus) is the speed of the transfer between the CPU - Northbridge and Memory. The CPU FSB can be double or quad pumped like on the Athlons or P4s hence the 200mhz FSB's. The FSB is also used to determine the rate of the PCI and AGP cards. Using a chip (or crystal possibly) the frequency can be divided hence dividers (1/2 1/3 1/4 and 1/5). These make lower frequencies for the PCI and AGP cards. The multiplier is what the frequency is multiplied by on the CPU for the working total frequency of the CPU.

If you have a 100Mhz FSB and an Athlon(700Mhz). Then you're CPU FSB is 200Mhz. Your memory can be 1:1 ratio or 3:4 ration so it can be at 100Mhz or 133Mhz. You PCI slot will be a 1/3 divider so 33.3mhz and your AGP 2/3 divider so 66Mhz (not sure on this. AGP may have it's own frequency). Your multiplier will be 7.

-Peter