Microsoft just rolled out the first publicly available release candidate for Service Pack 1 of Windows Vista, and we snapped it up, eager to see if it's faster than the currently shipping version of Vista. To test its speed, we ran a series of benchmarks on exactly the same machine, first with the original version of Vista, and then with Release Candidate 1 (RC1) of the upcoming Service Pack 1 (SP1). For comparison, on exactly the same machine and on an identical hard disk, we also tested those benchmarks using Windows XP. From the perspective of sheer speed, has Microsoft improved Vista with this first iteration of a service pack? Yes and no.