HOw much ram?
 

How much ram should i have for a server that doesnt run a lot of heavy virtual hosts? I do tend to run a lot of programs at the same time though in KDE, I have 2GB of DDR 400 (I think its 400) and can take a total of 4GB.

Also if I were to stick in 2 1gb sticks of pc2700 would that slow down the existing 2gb of ddr memory to pc2700?

I learned a long time ago that no matter what os a computer shall eat as much ram as you feed it. :)

And about the question of the twoo sticks... the speed difference can't be noticed unless you're benchmarking it, so it dont matter.

In response to the two part of your question. If your memory bus is running at whatever DDR400 is, using slowing memory will be 'overclocking' it to that faster speed. I've never had a problem doing that, but the risk is there that the memory won't be able to run at that faster speed and become damaged or corrupt. I doubt it will happen, but there is a chance that it could.