Or...How I learned there is a difference in Thermal Compounds (the hard way).
I was having a problem with my computer running W7 - monitor going black and keyboard lockup causing me to force shutdown and restart. Decided to pop the hood and re-seat the graphics card. What I found looked like the inside of a vacuum cleaner.
When I assembled this thing I had used the Thermal Compound that came with the kit and it was all but completely gone. After a complete cleaning I goobed it up with Arctic Silver 5 that I had left over from another project. What really shocked me is that it was always very noisy but now the fan was barely audible. So I guess with the fan working so hard it was caking everything with dust and causing it to spin even faster. All quiet now and it only shuts down when I say.