As the title says, I started having issues very suddenly. Last night I was able to play just fine, this evening I am having severe issues. The sound lags constantly, loading screens take forever. I had had occasionally hang ups in large fights before, but now it is regular.

I know this has tended to happen in heavily modded games with large save files. But I am not running any mods, save for a few ini tweaks I am running vanilla Skyrim. Any my save file is only 8mb, not that large compared to other peoples'.

Any advice? Why did this start so suddenly?

I should probably add that one of the ini tweaks is ugrids.

Try that:

1. Alt-Tab out of your game (if you don't have any other apps open to Alt-Tab to, press Control-Alt-Delete and start task manager which will get you back to windows)
2. Open Skyrim.ini, modify ugridstoload=5, or whatever lower value you want. SAVE the file
3. Alt-Tab back into your game
4. Open the console (~), type refreshini - this will reload the ini settings into Skyrim, with the lower ugrids value.
5. Close the console, save your game.
6. Restart Skyrim and load your game.

Thanks for the reply and the tip. I will keep that in mind for future reference but for now the issue seems solved. I checked the cache integrity via steam and it redownloaded one file. The issue seems gone for now.

Well, if you say so. Have fun. !!!