I have been playing for about a week with no problems at all. i have reached level 15 and all of a sudden the game is going really slow and gittery. can anyone please explain why

The FPS before and after is unlimited

gromul - fps is same in all saves and it was brilliant before not sure what exactly it was but the game was really smooth now its not. i have not installed any mods and all the settings are still just on high

Can you post the fps before and after.

the FPS is still set to unlimited

He means the actual frames per seconds you had before vs the ones you have now. (for example: used to have 50fps, now only 15)

Is the fps lower in all you savegames (like in the ones you were sub-level 15), or just the recent ones?
Have you installed any mods?
When did the lower framerates start? The 1.07 patch set all my settings back to ultra detail, even though I had some set at high before. Maybe this happened to you?