Oh I meant to say that I found this weird Windows 7 feature/bug that causes some games to only run in 1080i mode, or some games to lock up completely (Bioshock you git).
Windows 7 sticks closely to the HDMI spec of having 59.xxxHz instead of 60Hz refresh. This works fine in most games, but some games it causes problems like CoH, RE5, Gears Of War, and Bioshock.
This is a problem on nVidia and ATI cards.
The fix is pretty simple... you need to make a new custom resolution that has a refresh rate of 60.001Hz. This means vsync works better, you will always get 1080p, and should eliminate any potential problems like Bioshock not working.
Strangely most of the problems are when you use DX10 modes, as these select the refresh in a weird way compared to DX9 or DX11.
Here's a solution for nVidia cards, but you can do the same using ATI as well:
Screen Refresh Rate - Custom for NVIDIA Brand - Windows 7 Forums