FPS Drop?

So I just upgraded my pc. I have an EVGA GTX 770 (4gb)
CPU is an FX 9590 (8x 4.7ghz)
Everything is running pretty damn cool. (29c for the card.)

Randomly I can be walking around and the screen will freeze as I drop to 0 fps. I haven't had this happen in a dungeon yet, but definitely don't want to.

Any ideas why?

EDIT: I turned the graphics to max and it isn't happening now.

So apparently one of the settings was making my screen freeze every 5-10 seconds

EDIT 2: So my screen went black in a dungeon and people were jumping from spot to spot rather than running.