Edin Kadribasic has posted some benchmarks he's created from the Zend bench.php tool on the latest build he's created with the new version of Visual Studio from Microsoft.
Here is the comparison of running Zend/bench.php from the PHP source using VC++ 8.0 (Visual Studio 2005) and VC++ 6.0. The test was done on my Lenovo laptop with Celron M 1.6 GHz processor and 1.5 GB ram.
Overall, the differences are pretty minimal, but there are a few places that stand out and have more of a variance than the others (like the 12% difference in the "simplecall" test). Check out the post for the full list of the benchmark results.