Have you tried to start a new game with a fresh character? There is a possibility your savegames are too bloated. You can try fixing them (if is the case), Wrye's bash had that option for former Bethesda games, I did not try it with Skyrim and have not it installed at this moment to grant it is still there, you should try it. PS: Anyway you should expect framerate drops in some exterior areas. Skyrim is a game highly dependent on CPU power also and can bottleneck in some places, like locations with many concurrent AIs from NPCs. A combination of high graphical demand with high CPU demand can be a performance killer. Having vertical synch enabled can be a factor too, leading to severe framerate drops if the nominal value for your monitor refresh rate can't be achieved by the video card, sometimes 50% drop or more. I recently deleted All my saves and the entire skyrim folder and started a new game only to get the same results. The game runs fine, i usually get around 50fps outdoors but as soon as i go indoors then back out 15fps :( It runs as it should normal indoors 60+ fps
