Why does Rage the video game by id software lags?

intel i5 2500k

8gig ddr3 ram

nvidia 560ti 1 gig ddr5 vid ram

1080i res

with this awesomeness system i should have no problem running this game. The game runs really sweet but when i go from inside the building to outside i start getting like 1-5 fps for like 2-3 mins then it goes away...i'd really like to say, "oh it's just the game loading all the textures and stuff" the thing is it doesnt do it when i first start the game. If i'm outside and i start the game it is running fine. There is a bug that is causing this. Some sorta screw up with the game, not my computer. I've reinstalled drivers etc but this game still does that. I tried google and i can't find this specific problem which makes me think it is my rig. I can run skyrim with settings all maxed out and get like 30 fps and it is way more demanding so why would this game only give me 1-5 for those first few minutes coming from inside a building to outside.