Microsoft has gone on the offensive over a performance testing result which found that XP, with its Beta SP3, is faster than Vista with SP1. The benchmarking was done by Devil Mountain Software and attracted a fair amount of media attention.

Now Nick White, a Vista Program Manager at Microsoft, said that the benchmarking was bogus as the performance of the service pack updates is still “a moving target.” He said that publishing the benchmark results now was not “a worthwhile exercise.”