ZD Net got its hands on the Windows 7 RC and compared this operating system's performance with Windows Vista SP1 in three games with four different graphics cards. You can check out the results over here, but it's hard to compare as the author wasn't allowed to publish the actual results. Based on the article's bar graphs, it appears the performance of Windows 7 RC is pretty good.
So, what’s the takeaway? It seems to me that there’s little difference between Vista SP1 and 7 RC when it comes to gaming. This is both good news and bad news. It’s good news in that gamers who shift to Windows 7 won’t suffer the disadvantages that those who made the leap to Vista when it was released suffered. It’s bad news though for those expecting to unlock more performance from their system.