It realy depends on how much memory all your other programs use. My P4 only has 256mb of ram and I have Prime95 set to use 96. I only do so, because when use the system I usualy only use about 100 mb of it. But as mentioned the client will only use like 30mb or so when doing the LL's, etc. The only time it will use the full amount that you give it is when it's doing the P1 tests I think.