But it’s not all bad news with Windows 7. Microsoft’s new OS has a clear multicore scalability advantage over both Windows XP and Windows Vista, especially on less I/O-bound tasks like our multiprocess database workload. (We can thank SQL Server 2008 for that one.) In fact, with its second-generation multicore tweaking (good-bye, global lock!), Windows 7 is poised to overtake XP even earlier than Windows Vista — perhaps at 16 or 24 cores. In the meantime, you certainly won’t lose anything by moving from Vista to Windows 7, and you may even gain a few seconds here and there, thanks to its better kernel tuning.

In Randall’s database transactions tests, Windows 7 would need to run on 16 to 24 core systems before it can match Windows XP in speed.