I'd have to agree w/ everybody else. 512 in dual channel mode should be able to run in regular mode (depending on your MoBo) if you need the extra headroom for RAM. If you decide to take that option, there
may be a slight performance loss b/c the ram is running in single channel mode instead of dual; but then again the 'extra' headroom may allow you somewhat compensate for the speed reduction. I am also in the process of building a very similar system, but with a P4 640 instead. If you decide to spend the extra $$ and go for the 2x1 Gig in dual channel, make sure that you get it from a reputable manufacturer. New Egg is a good place to start. I was out of the loop for a while but after a few weeks of scowering [url]hardforum.com[/url] (many sleepless nights) I was able to make a more informed decision on which MoBo, CPU, RAM, etc. I was going use to build my system; If you want to see what some of the 'big boys' use, this is a pretty good place to start, even if you aren't going to over clock your system...
that's just my .02
