I have recently seen this post by Mathew Hardman about their work with a customer on PHP on windows. The test were saying that these results would come out, but having the real tests with customers is a different thing.

So their work with a local Singaporean travel portal StreetDirectory.com yielded the folow,ing results using PHP on Windows Server 2008 and FASTCGI.

One interesting thins is that They just got the applications and put that on a Windows 2008 Core servers with no performance  Tuning, just out of the box.

The report can be downloaded from Mathew's Sky Drive here,