1GB HD 6950 marginally slower than 2GB model

More than a match for the GTX 560 Ti
In a series of real life tests the 1GB version was just marginally slower than the 2GB model and in most 1080 tests the difference is negligible. In most tests card also managed to outperform Nvidia’s GTX 560 Ti, although Nvidia proved faster in some titles, such as DIRT 2 and Lost Planet 2. On average the 1GB card was 5 percent slower than the 2GB version, but it’s also 5 percent faster than the GTX 560 Ti.
All in all it appears that the reduction in memory size had very little effect on performance. So, it’s about 10 percent cheaper than the full blown 2GB version, yet just 5 percent slower, so it’s clearly very good value.
You can check out the review here.