Q: im wondering which one is better ??? of course X2 got 2GB and 2 HD4879 got only 1GB, but how about the speed ??? sorry, i meant 4870 not 4879 (my bad in typing)
A: The X2 should be better once the drivers are mature. There's extra bandwidth between the chips on the X2 and more memory on the board. The reference frequencies are the same, but the 4870 might have more overclocking head room.