You'd be better off getting another 512mb version. My understanding is that games will only be able to use 512mb on the 1gb card. This would be wasting half of the memory, and would really defeat the purpose of getting it. If I'm wrong on this, someone please correct me.
the 1gb model does show minimal fps increase at 1680x1050, but not much too justify the price increase... if your resolution is 1920x1080 or higher, than you should consider swapping cards. otherwise no.
BUT since you were considering getting a 1gb model to cf, why don't you just buy another 512 card and crossfire it? it'll be the best choice yet
I gotta concur. Forget about the 1 gig card, and simply CF another 4870 512. The extra memory 95% of the time, unless you are gaming at uber high res won't help a thing. Even then, it's a very small benefit over your 512 meg card.
Now, CF'ing 2 512 meg 4870's will allow to crank up the res, the eye candy, and flex plenty of horspower to keep things moving very nicely.
Much, much, way much better plan.