Well I have had this problem for a while, and I have seen a lot of people complaining about it, but I've never seen a fix for it. About 30 minutes into the game when I enter/leave a building in skyrim, my game goes from 60 FPS to like 2-3 FPS, the game basically turns into a slideshow. Sometimes if I wait 10 seconds the lagging stops, but most of the time the game has to be restarted to work normally again. My computer is powerful enough to play this game on ultra without lags, and the interesting thing is, even if I put all settings on low, this problem still happens. I have tried the ENBoost mod since i heard someone suggest it on the forum and it did not help.

My computer specs:

Intel Core i5 CPU 750 @ 2.67 GHz

RAM 8 GB

Win 7 64bit

NVidia GeForce GTX 275 4GB VRAM