The venerable 2001 classic of an OS, Windows XP, strikes again. The scribes over at Laptop have put together a rather damning battery life comparison between old greybeard and the fresh Windows 7, which finds that on average netbooks get 47 minutes less battery life with the upgraded software. In the case of the ASUS 1008HA, that deficit was a meaty 57 minutes, or 16.7%. Liliputing and jkOnTheRun have run their own tests which invariably reached the same conclusion. Adding these data to an earlier comparison with Snow Leopard, where Windows 7 was again markedly worse than its competitor, leads us to the conclusion that perhaps Microsoft's 7th heaven hasn't quite been optimized for the mobile mavens out there... yet.