Re: Crossfire HD 4870 choice
Basically, if you have a 1gb in 4870 and 4870 to 512 mb, 1gb the work to 512 mb (it will therefore in the least powerful). Because the cards together, it must be identical. If one is more powerful, it will lower its performance to be at the level of the less powerful.
Basically you pass in: 4870 1gb + 4870 512 MB
to: 4870 512mb (1gb original) + 4870 512mb.
Re: Crossfire HD 4870 choice
Crossfire is useless, the 4870 is sufficient alone to play all games of the moment (Crysis is not a game, rather expect the next generation of chips DirectX 11, your money will waste. you may wait a long time for games in directx 11, so long that the world will be on xp there is not really a lot (kind of games like crysis that will require many resources).