There's another post about measuring performance but at least one solution I looked at (NovaBench) measures pure performance of the hardware. (I.e., disk read/write performance, rather than the actual performance when taking into account disk fragmentation, etc.).
I want to measure the effective performance of the PC (i.e., how quickly my various programs will run) and that is affected by how much cruft is bulit up in the system, how fragmented the harddrive is , etc.
Any suggestions of how to measure the actual performance?