Found this somewhere else and thought I'd share:
This week many PC gamers have sat down with a shiny new copy of StarCraft II to play. They
Amazingly, this is not all that uncommon for games to not cap FPS in menus....
The problem (IMO) is modern hardware not capable of running at 100%... What good is gear that is only as fast as it running 80% of capacity? Do people read benchmarks and scale back 80%? Nope :).
I used to use Sacred 2 Menus as a torture test for OCing... as it did the same thing :)..
Usually Vsync will fix this (as the res will cap to your monitor refresh rate [usually 60 - 85hz]