P4 800FSB Backwards Compatible to 400FSB?

[shasta66]

I have a Soyo SY-P4S645D motherboard with 400/533FSB. I only have a 1.8GHZ chip & want to upgrade to a 2.8 or 3.0 w/hyperthreading. Will a chip with an 800FSB work in this machine. If so, what are the pros & cons? If it wouldn't hurt anything it would be nice to have the 800FSB for when I can upgrade the motherboard & the prices are about the same. I even noticed at least one 800FSB being cheaper than the 400FSB.

Sincrest thanks. I greatly enjoy coming to read posts at this site from time to time, it is always a learning experience.

 

[mrSHEiK124]

whoa! go ahead and bless your system with a new mobo, better yet, buy an AMD 64 !
but if you must go intel, get one of the new 9x5 boards with PCI-E and Socket 775, and use that system for a hand me down

 

[nick1985]

go with an A64

 

[rond36]

The fastest processor that motherboard will handle is the P4 2.8B 533MHz FSB 512 cache and no HT

You may or may not be able to use the P4 3.06C 533MHz 512 cache with HT but your MB does not support HT so it will be dissabled

Your board does not support 800MHz FSB the max FSB is 555MHz or HT or Prescott CPUs

 

[VirtualLarry]

Originally posted by: shasta66
I have a Soyo SY-P4S645D motherboard with 400/533FSB. I only have a 1.8GHZ chip & want to upgrade to a 2.8 or 3.0 w/hyperthreading. Will a chip with an 800FSB work in this machine. If so, what are the pros & cons? If it wouldn't hurt anything it would be nice to have the 800FSB for when I can upgrade the motherboard & the prices are about the same. I even noticed at least one 800FSB being cheaper than the 400FSB.

Sincrest thanks. I greatly enjoy coming to read posts at this site from time to time, it is always a learning experience.

There's always one more alternative - you could try to obtain a faster P4 Northwood "ES" version, off of E-Bay. "ES" means Engineering Sample, and generally those are not multiplier-locked like the regular chips. You could therefore run the chip at a 533Mhz FSB, and then adjust the multiplier upwards to reach the desired speed. The problem is that these chips are slightly rare, and might cost more than a regular chip of the same speed. The other alternative would be to buy a higher-clocked Northwood chip, and run it at 533Mhz FSB, and it would necessarily run slower than spec.

You should check your motherboard manual, but I don't think that your system can handle a Prescott P4 chip, seeing as how it doesn't even handle 800FSB chips. Don't accidentally buy a 2.4Ghz 533Mhz non-HT chip that turns out to be a Prescott. You can tell, because they have 1MB L2 and are 90nm. Northwoods have 512KB L2 and are 130nm.

Btw, does your board and/or chipset support Hyperthreading? Hmm, after looking up that board, it does not support Prescott, Hyperthreading, or a P4 CPU faster than 2.8Ghz, according to the Soyo site.
Sorry.

board specs
CPU support

 

[stevty2889]

I would highly recomend trying to run an 800MHz fsb proccessor on the board if it doesn't support it, even if you could set the FSB to that speed. I tried to run my 3.06ghz cpu on a 400mhz FSB motherboard, that could overclock to 533fsb, and the motherboard went up in smoke...