Questions in the subject line really,

Can I use a 400Mhz AMD with 333Mhz memory?

I have 1gig of 2700 memory in my 400Mhz gigabyte motherboard, a GA-7N400 Pro and am looking to put a 3000XP in it which comes in 333Mhz and 400Mhz.

Will the 400Mhz one work?

It will work since you can run the Ram out of sync with the FSB but performance will be quite low ( much lower then running the FSB & the Ram at 333 ).

good point Didou,,i currently have pc-2100 im my pc,,when i first set it up i looked in the BIOS to make sure i got the 2.08Ghz from my XP2800 and the mem ran at 266,,it was very slow,,like "80486" kinda slow,,then i thought,,,i had this mem OC'd to 333 with my P4,, so i set my FSB/MEM to 1:1,,things are great,stable and good to go.

true. in an ideal world, you should buy the fastest ram you can get hold of and jack up the ratio, i think you can get PC4500 now. But slower ram slows the entire FSB(a bit).

It may work but it will slow the processor down a bit every times the processor accesses the memory.

And how often does it access the RAM... a million times a second?

The whole point is whay buy a 400Mhz FSB processor and then get slower RAM. May as well get the fastest 333Mhz FSB processor.

Because he can always upgrade later perhaps? Plus the 400mhz fsb processor will still be faster (if the ram is in sync) then a 333mhz fsb. The FSB speed isnt everything, however it is a large factor.

Still really, your right, you ought to save yourself the cash and get a 333mhz fsb cpu if you wont be upgrading your ram any time soon.

Best Bet: Get the 400mhz fsb xp3000 and run it @ 333mhz fsb with the multiplier @ 13.This is what the 333mhz fsb xp3000 runs at stock around 2.17 ghz.Then later upgrade the ram and bump it up to 400.Dont forget to set the multiplier back to auto before the change though.

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Im running my processor at 400mhz and memory at 333 with no problems. If you have 333 ram you could probably OC it to 400. My ram is PC2100 but Ive always run it at 2700.

The problem is that he has an nForce based motherboard & they react very badly to asynchronous memory/FSB modes.

If the chip is indeed unlocked ( you can never be sure about that before you actually purchase the chip & try it out ) then you could do as Korperal sais & lower the FSB while raising the multiplier to have the same performance.

If the chip happens to be locked, you'll only be able to run it at 1743mhz ( 10.5 x 166mhz ) which is quite far from its rated speed ( ~2167mhz ).

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