What is the Multiplyer used for in overclocking?

[Marion]

I am new to overclocking and am told I can't change just the multiplyer to change my CPU speed. In other words on my PIII 750 I can't change the multilyer to 8.5 to change the CPU speed to 850Mhz. I must also change the FSB to some higher value. If this is the case what purpose does the multiplyer serve? Also If I set the FSB to 133 or higher I know it will also affect the PCI and AGP speeds. How much of a concern is this? Thanks!

[atek]

i am new to o/c also, but what i have learned:
intel locks the multipliers on their cpu, you can only adjust the fsb to o/c

agp and pci are o/c when changing fsb - pci wants to be at 33mhz. and agp at 66mhz. adjust divider(2/3,1/4,etc.) multiplied times fsb to keep these close to the desired mhz.

you might need to up the cpu and i/o voltage to stabalize your o/c.

your memory (preferably pc 133 or 150) and video card may also need to be tweaked. also watch cpu temperatures, may need new heatsink
and fans.

here is a good site for beginers. read alot before trying.
http://bxboards.com/tips.shtml
hope this helps.

[batboy]

Clock multiplier times bus speed equals processor speed. On a P-III 750e, the multipier is 7.5 which as was noted, can't be changed. If you have a good motherboard, the ideal thing you can do with that chip is run it at 133 MHz. Since this is a default setting for some P-III CPU's, there are the proper PCI and AGP dividers so they are not running out of spec. The beauty is... that just happens to make the 750 run at 1 gig. You need to have the best cooling, and use PC133 RAM, etc. and still only about 50 % or less will overclock that high. Overclocking is not a sure thing. Some chips are good and some are dogs.

[[OC]_SR20DE]

Actually...dude,

you dont have to have the best cooling to run 750E's @ 1000. Depending on what stepping type/wk# will also considerably make the difference for the CPU to handle the heat when OC'ed the hell out of it. hehe. I got no special cooling. I got cC0 700E. whatever the method of cooling is....., as long as you see the tempertures stay in reasonable level(30 to 44C) you are good to go ;P