the time has finally come for me to build a new gaming computer and i have come across a problem; i am stupid when it comes to graphics cards. i know enough to know what is powerful, but i have troubles with SLI/Crossfire. for my new rig, i have been looking at the GTX 550 Ti 2GB card from EVGA, which is fairly cheap, so i kinda want to get two, but i also have been looking at the GTX 570 2GB, also from EVGA, which is about twice the cost. i am stuck on which would perform better, the two 550s or the single 570, and since both setups would cost about the same, i am unconcerned about price and i am solely looking for better performance. anyone got any ideas? before anyone asks, yes, the new Mobo and PSU i have picked out will support the two 550s, and my case is big enough to fit them.
If you have 16x16x or 8x8x SLI capability, I would suggest the single GTX 570. It will handle any game you want to play at 1920x1080 and less resolution. A 2nd GTX 570 can be added later. If you are only running 1 monitor, you can save some $$ by going with a 1280MB GTX 570 card. Of course, you will need a suitable PSU if you go with 2 GTX 570s later: http://www.thermaltake.outervision.com/ (PSU calculator)
2 GTX 550ti's may be the equal (or better) of a single GTX 570, but then that is a dead end.
you should always go for the single card over dual cards if they perform about the same. check out some of the reviews on techreport.com. Look at the frametime readings vs. frames per second for the sli review vs. single card. You'll never want to go dual card after reading some of it...