would running two 512mb=1gb of corsair xms memory at ddr 400 3200 not in dual chanell or running those 512's with a 256 mb in third slot at ddr 333 be better.
Hold on, let me refrase, I have 2 512mb of corsair in now, which is ddr 400, 3200. My motherboard has three slots but when 3 sticks are in, it can only run max at 333, so would running two 512s at ddr400, be better then running those with an extra 256 but only at ddr333.
Personally I would stick with 1GB at 400 rather than 1.25GB at 333. Just my opinion. It all depends on what you need to do, as the extra memory may let you open more windows and multi task more (Marginally) but for gaming and things I think you would actually be running slower.
You may even find that the 256 doesn't whant to play with the 2x512. Memory is a funny thing.
If in doubt, try it and run a benchmark before & after, like Sisoft Sandra (Free download) and it will tell you if there is any difference in speed. Go on, you got me interested now
MAYBE if it was 2gb of DDR333 vs 1gb of DDR400 it'd be a tougher decision....but your losing quite a bit of memory bandwidth for a minimal gain in actual memory space....