Why have vsync on? and my scheduled virus scan isnt at this time so :?
I never understand why people won't turn on V-sync. It removes screen tearing and keeps your GPU from going overboard when it's unneeded.
You get 120fps? Sorry to say that it doesnt matter, unless your monitor can handle seeing that many, and my guess is that it's a nice 60Hz monitor that would benefit greatly from having Vsync on. Have a 120Hz monitor? Cool, then you might be better off not turning it on.
A good example of where it helps - have any of you played alien swarm? It's a free game on Steam. If you don't have vsync turned on, well at least for a few of my friends and myself, it would render parts of the game too fast; I was getting almost 1000fps on the menu screen. Because of this, my GPU was grinding away to calculate those, and made it jump from 43 degrees to 104 degrees in about 2 minutes and BSOD'd my computer.
Turn on vsync and walah, a steady 60fps.
It's old, but here's a nice explaination of Vsync:
http://hardforum.com/showthread.php?t=928593