Upgrading computer question...

[Mobius]

I want to buy the ASUS P4C800-E motherboard. However the problem is I haven't been paying attention to computers for the last few years and have a question.

This is what it's memory specification is.
MEMORY: 4x 184-pin DIMMS FOR PC3200/2700/2100 (DDR400/333/266) up to 4GB (ECC SUPPORT,DUAL CHANNEL)

What would happen or is it possible to use PC4000 DDR512 memory instead or do I have to stick with the PC3200?

I need to keep my upgrade under $600.

ASUS P4C800-E $178
Pentium 2.4GHZ 800 $163
PC4000 DDR 512 x 2 $154

TOTAL = $495

That's what I plan on buying once my memory question is answered. I also need to look for a cheap but good video card too.