Geekbench
This test from Primate Labs runs a series of geeky tests like prime number, Mandelbrot, blowfish encryption, text compression, image sharpen and blur, and a memory stream test. The subtests comprise both single- and multithreaded applications. These tests are hardware intensive, but I did indeed see incremental improvements when upgrading Windows—both from XP to Vista, and again from Vista to Windows 7.

The most astounding result I encountered was the improvement in JavaScript performance, as evidenced by the SunSpider benchmark: Windows 7 was 42 percent better than XP, and 26 percent better than Vista on this test. When I contacted a Microsoft representative, he said that this was "pretty closely in line" with what Windows 7 product managers have seen. I ran the benchmark using Firefox 3.5 on all three Windows versions, to level the browser software playing field. I contacted Mozilla for a comment on their browser's striking improvement under Windows 7, but no one was available for comment—they were all "heads down on Firefox 3.6.

Windows 7 Performance Conclusions
For the most part, these tests don't show Windows 7 soundly trouncing XP. But for an operating system that's far richer in features and more advanced in interface, Windows 7 is quite close to the older OS and tops it in several tests. Most impressive among Windows 7's wins were its JavaScript and shutdown time results. Maybe most telling was that Windows 7 beat Vista on every test. But to that much-belittled OS's credit, Vista actually shut down faster and performed 16 percent better on SunSpider than XP, even if it took significantly longer to start up.

Though it may be unreasonable to expect faster performance alongside more interface and convenience features and lower requirements, I was still disappointed not to see Windows 7 top all these tests, particularly that for startup speed, given the promises Microsoft made one Window's behalf. The much faster JavaScript performance in Windows 7 will become increasingly important for a vast number of users as Web applications become richer and richer. For gamers, the results are pretty much a wash between XP and Windows 7. In any case, power gamers are far more likely to be buying for a new high-end machines and not upgrading an old XP system.

In all, I think Windows 7's performance gains are welcome steps toward ending the reputation Microsoft's operating systems have gotten for code bloat. On none of the tests did Windows 7 score last among the three versions of Windows tested. XP, which is finally starting to show its age, scored dead last in three. While these results aren't unalloyed good news for Windows 7, they do show that Microsoft seems to have finally woken up to the fact that it shouldn't rely on Moore's Law to deliver ever-increasing processing to handle ever-more bloated operating systems. This can only be a good thing, especially given the current demand for low-power, low-cost netbooks.