Trying to install HD Tach in Vista will give you an error like this:

If you try to run the program in Compatibility mode for Windows XP SP2 as an administrator it will work.
This is how disk performance looks with HD Tach on Windows Vista Ultimate 32-bit with a pair of Western Digital Raptor WD1500ADFD 150GB 10,000 RPM Serial ATA150 Hard Drives in RAID0 with the Intel controller on the Intel D975XBX Bad Axe motherboard.

The burst speed is an impresive 243.7MB/s with the average read speed being 131.0 MB/Sec. These drives replaced my aging WD2500 hard drive that I wasn't running in RAID. The best it could get was a 168MB/s burst speed and 55.5 MB/Sec average read speed on Windows XP Pro.