True, DX11 does work on DX10 cards but how do you think about a card that was configured for an API that it doesn't even know, Thinking about how that would perform in benchmarks is like playing chess in the dark. Take Vista for example, when it was first released, Microsoft claimed too much on things that Vista can only do well at first with a system that cost more than 10 used cars at a dealership on Chinatown. Basically, the whole PC community went to hell, especially when upgrades that finally fixed the problem rolled along right after people spent thousands with the exact same impression:shadedshu. So hear me out on this one: even though DX10 and 10.1 based cards work with DX11 AS CLAIMED, do you want to take a chance in OS claims that have chance of never existing? As for Windows 7, I do have some sense of confidence that hardware would eventually catch up but in the mean time, however today's OS's and game engines have been years ahead over hardware since '04, and the only kind of hardware that is somewhat generations ahead is quad and eight core processors, as they have some potential of 128-bit interfaces and multi-threading technologies. In the mean time, I will be looking for a 128-bit OS in the future