2 4870x2 vs a single 5970?

In a perfect scaling world the 4870x2's should win. However I would expect, without having seen any specific benchmarks for the 5970 to win due solely as it is easier to use it's full power.

is it worthit to sell a 4870x2 and get a 5970?

im noticing that most games, esp the newer ones are just now starting to use the 4000 series graphics cards from ati for instance.. in addition to others..

Nope, I wouldn't sell it.

I doubt you are experiencing any real slowness in fps are you? I would wait till later on this year and see how things stand.

Prices for one will probably have dropped.

well I just finished mass effect 2 with a steady 60 fps ad 2048x1152...
so not really..the only game that seems to have fps issues is crysis for some reason..they fluctuate a lot from 60 fps to 15 in a matter of seconds..

Id wait til th next gen gents, those are fine cards, and the 5870, fermi etc on up wont be needed til next gen, when games will finally need more

I wonder if I will be able to play crysis 2 or avp with max settings using these cards

Crysis 2 is unknown as although they state the pc version will be for the pc it is also a cross platform version so who knows.

Obviously with AVP it might use some dx11 stuff but I am not sure how much and if it will be noticable. Really you have nothing to lose by waiting until the time that you cannot get the performance you want.

The tessellation on AvP will probably need a 5850 minimum to use it fully.
A 5970 will be an upgrade, but at that resolution you probably won't notice 60FPS to 80FPS.
5970 really shines at 2560 x 1600 with AA and 3 * 1920x1080.

I predict Crysis 2 is a graphical downgrade since they made it available to the relatively weak hardware of the consoles.

CryENGINE 2 on consoles is Low on PC.