I'm really new to this, so maybe you could help me out--are these two cards Crossfire compatible with each other, or do you have to have the exact same card, by the exact same manufacturer in order to work it that way? Because I'm very interested. I'm running a single HD 4890 now, and although I'd ideally like to crossfire those, running two cards that equate to 5770 (more or less) would still give me a performance boost. Here's hoping you haven't sold them yet. =]
You can crossfire any two similar "chips". For example, any two 4870's and be crossfired, regardless of brand. In fact, I'm running these two (differently branded) 4870's right now, in crossfire mode. The same is true with basically all other video cards made by amd/ati.
If you were wanting some indicator of performance, the games I've played are battlefield bad company 2, civilizations 4,Civilization 5, and left 4 dead 1 and 2.
I play at 1920x1200 and can Vsync BFBC2 at 60 FPS with 8x AA and all the eye candy,
L4D 1 and 2 are easily VSynced at any setting
I've never really measured Civ 4,Civ 5, but I've never noticed a noticeable lag or slowdown
I can't comment on newer games, but I hope you can use these as something of a performance gauge.
For the rest of the system specs check out my profile. I'll have them for a while, I hadn't gotten around to putting them ebay yet due to the holiday craze. Let me know.
Edit: It was supposed to read Civilization 5, not civilization 4. Sorry for the mistake.