i recently built a mid-range system (i.e., around 1500 w/ monitor) and went with the gtx 275. i've been happy so far, but my large monitor resolution (1900 x 1200) is pushing the card a bit, in games such as empire: total war. it's not as silky smooth, as i'd like.
i'm thinking about selling off my 275 and going with a higher-end model (i'll lose some money in this process, no doubt), or going sli with two 275 (my motherboard is made for it). i'm a little concerned after reading the faq, however, and seeing my vram will still be limited to one of the 275's which is 876 ram, or whatever that number is (can't remember!)
Wargames of that type tend to be heavy on the CPU, so check for and apply any patches there are first.
Do the usual cleanup: Check for running programs/processes and disable or uninstall as required. Run a virus/malware/spyware sweep in Safe Mode (some of the little darlings can hide from a sweep in normal operation).
Check the detail settings of the games: Shadows and AA can quickly bring even the most massively powerful PC to its knees if used unwisely.
thanks for the tips guys. my mobo came with some software called "easy tune" which should be an easy way to give a modest jump to my cpu, etc, and i think i can disable a couple superfluous eye candy components.
interestingly, it's really only the water that gets choppy. land battles are smooth.