I tried a CUDA benchmarking tool that can be downloaded here.

It works well for CC1.2, CC1.3 and presumably CC1.1 cards, but not for Fermi cards!

Might give people an immediate idea of OC improvements or relative card speeds. It can also be used to look at stability, though you will have to click on the X in the top right corner to close it.

Example:
GeForce GT 240 @ 1624MHz Shader Clock - 11.7sec for 250000 test.

GeForce GTX260 @ 1537MHz Shader Clock - 6.6sec for 250000 test. (sp216)

Remember it is always advisable to close Boinc before running any such tests.