From what we've seen so far Windows 7 is already performing better than Vista, but if your PC seems sluggish then it's now much easier to uncover the bottleneck. Click Start, type RESMON and press Enter to launch the Resource Monitor, then click the CPU, Memory, Disk or Network tabs. Windows 7 will immediately show which processes are hogging the most system resources.
The CPU view is particularly useful, and provides something like a more powerful version of Task Manager. If a program has locked up, for example, then right-click its name in the list and select Analyze Process. Windows will then try to tell you why it's hanging - the program might be waiting for another process, perhaps - which could give you the information you need to fix the problem.