The only problem is I have read some reviews and heard that for instance on bf3, the game will crash after about half hour because of this card. Is this really true or are some customers installing it wrong?
Either the HD6950 or the 560Ti are both adequate cards for your needs, and they both offer 2GB versions. Nvidia has less frustrating driver issues but neither are deal breakers. I believe the HD6950 may perform slightly better in benchmarks but in real world game play there is no difference. I recommend a non-reference model with good quiet cooling.
@PresidentSwag, Go with the ASUS GTX 560Ti DirectCUii Top. It runs much cooler, it has lots of headroom for overclocking, looks good, build quality is superb. If u have money, space; I recommend you to go for two of those, you might get 35+FPS in bf3 @ ultra settings.