CPU Compatibility Question

[rhawk79]

I'm sorry that this is a double post from the general forum...i just realized there's a cpu forum and i'd delete the other thread but i guess you can't do it on this site.

I'm about to sell my 850E motherboard and p4 2.4 533 to buy an 875 based board and a p4 2.8 800mhz bus cpu.

Question tho, if I receive my CPU first can I use the newer 800mhz bus based p4 in an 850E board and have it run at 533? This will be while I'm waiting for my new motherboard. There may be sometime in between getting both parts because I have to sell the old ones first, but I don't want to send away my current p4 2.4 533 and not have a working computer for the week or two in between. My board is compatible with the p4 2.8 533 so can i throw in a p4 2.8 800 for the time being and just have it run at 533? Thanks!

 

[Canterwood]

I've tried underclocking my 2.4 800fsb chip on my 875 board, and it wont allow it. The Bios says its running at 133 (533fsb) but a closer inspection of wcpuid shows its still running at 200 (800fsb). I dont know if its just my board or whether its down to the cpu. I can overclock easily enough.
Another problem you might have is the hyperthreading on all the 800fsb cpu's.
Your board would have to support hyperthreading i would imagine.