writes: "While not conclusive, the SPEC group released benchmarks for a variety of systems submitted by various manufacturers (i.e. Dell, Compaq, HP, etc...) and tested their Web-serving capability. Two very similar machines from Dell, one loaded with Linux and the other with Win2000 had very different results; Linux beat Win2000 by a factor of almost 3 . Here's a synopsis of the results from LinuxToday. The actual spec benchmarks are available here for Win2000 and here for Linux."
As Marty of LinuxToday puts it, though, "What does this mean? In the real world, probably not as much as it would seem. Benchmarks in general are typically set up in an ideal environment. Real world environments tend to be quite different. However, this does indicate that Linux is moving in the right direction."
Zoran points out that "[o]ther current SPECweb99 results can be found here." They make an interesting comparison.