What is your PSU? brand? model? Tell us your full specs including monitor...
Well, actually, I'm planning on giving my old rig to my parents.
Old rig: 2.9 Athlon AMD 4850 1GB XFX 600W OCZ 4GB
For my new rig, I was thinking of getting a PSU in the 7xx-8xx range. 4-8GB of RAM a Core i7/i5 at <3.2 GHZ
Right now, I have a Samsung monitor at 1600 x 900, but I might get a Dell 1920 x 1080
4850 in crossfire would be the best performance wise, but your PSU would be a little overwelmed.
Save a little bit and get HD5850, it would be great for 1920x1080...
Okay, for me, I choose my PSU's after I've decided what parts, so, what would be a better buy? A 5000 series card, or two 4850's in CF
I always prefer a single card solution better than dual (CF/SLI) cards solution. And do not get the old tech like HD4xxx series, you'll better with 5xxx series, like HD5850 or even HD5870...
Definitely go with a single 5850. Power usage of the 4000 series cards are quite high, as well as a dead end in terms of future upgradability. And don't bother with more than 4gb of ram, it's not worth it.