"I spent literally hundreds of hours testing this, and I think the results are the first conclusive performance comparisons between Windows 8 and Windows 7, especially in gaming. I wanted to make sure that I didn't run any tests that were hardware limited.
For gaming performance, frames per second is not sufficient to portray actual gaming performance. This article looks at frame delivery times, in milliseconds, and shows pretty significant results depending on system configuration. For office applications, trace based benchmarks were used to show overall responsiveness using real workloads and real data."