Originally Posted by saltynay
Probably due to a difference in clock speeds as they use different clock architecture and prices fluctuate so much its very difficult to find 2 cards to compare. Its also due to core architecture which leads to difference in games like amd being better in some even though its benchmarks say its a worse card or cheaper then an nvidia gpu which gets less fps. Driver optimisation is another element and memory speed/amount it goes on forever.....
Yeh, drivers are quite a big one. Nvidia "normally" release with more optimised drivers than ATI (just going off past experience ppl) and alot of benchies are done at release. If you look at benchmarks now for a hd 4870 for example, they are getting a fair increase from release benchies because of newer drivers.