There are many programs.
You can try 3DMark03 (http://www.futuremark.com
) or 3DMark01 (same site)
There is also Aquamark (use google for link
) or SuperPi (for memory tests).
These are the most common used programs.
There are many others ofcourse.
Oh yeah, try to use the search-function of this forum and you'll find a lot of information