System info:

Intel Core i5 CPU 750 (dual core 2.67/2.67)
4 Gig RAM
GeForce GTX 275 Graphics Card with the lastes updated Nvidia drivers (290.36)
[Ambient Occlusion is set to performance, anti-anializing at x4 (recommended x16)]
64-bit Windows 7

SKSE with TESVAL 1.3

Problem:
I've been having some minor ”microstuttering” problems in external cells for a while now (usually never a problem indoors). I've been gradually reducing the graphics quality, testing to see if I could find a setting where the stutter would disappear. When I start the game, the graphics are smooth as silk and almost ”photorealistic,”, but after 5 to 10 minutes a small stutter starts in if I'm wandering anywhere out in the wilds. Just barely noticeable, and not a major problem, but interesting how it gradually builds up over time.

HOWEVER, today I started the game and the problem accelerated much much more quickly, going in the space of a couple of minutes from clean and smooth to microstutter to serious framerate choppiness. I've restarted both the game and my computer several times, reduced my graphics settings even further (to those current above), and the problem persists. It has also begun to show up in internal cells now, and is so severe as to make the game almost unplayable. The stutter makes its very difficult to focus on opponents in combat and so forth. Even the inventory and map are visibly effected, and save times are also effected (?). (If I play for a few minutes, it suddenly takes the game a very long time to load, save, or quit, much longer than before.)

For the life of me I can't figure out the problem. It was working fine last night. I haven't changed a thing on my computer since then. This morning I get up, turn it on, and suddenly the performance has fallen through the floor.

I can add one other piece of info: previously, while playing, I noticed how my computer would begin to work harder (the fans would begin to make noises). Today, despite the choppiness, the fans haven't kicked in and the computer is running as quitely as usually does.

Anyone have any ideas/advice/solutions? Thanks in advance.

for me after about an hour or two of playtime my fps reduced to below 10, sometimes its not even 2 hours, sometimes i just log to the game and i am in the wilds.. i start walking for a few min, 40-60 fps and im happy as a schoolgirl AND BOOM! 13 fps. i tried reloading, i tried pcb, nothing. quick raveled to another location and it somewhat solved it.. 30 fps. indoors i usually get 60 fps, 59 when i quickturn

Could your AV be scanning the game files as they're being used, or windows defender doing a scan? Or is windows updating? Or is windows defragging (scheduled)?

askin me? im using kaspersky pure

edit: i'll try to close it and see if it still happens.

Both mate.

If windows is doing something in the background, like the things I mentioned, you'll definitely lose a lot of performance in a game.

Use something to watch your video card's clock rates, I found what was happening with me vs the Nvidia beta drivers vs Skyrim is at some point the cards were told to drop down to stage 1 performance (instead of full performance) and regardless of what I did they'd stay in that mode: Kaboom heavy performance drop.

I fixed this by telling the Skyrim profile to insist upon full performance.

and how do you do that?

btw i closed my system care program and it made fps go up outside but i still felt some sudden drop downs here and there.. and one time where i entered a hut there are spots where my fps would go to 5 and if i moved from there it would go back.

Get and run Nvidia Inspector, open up its charting tool and make sure at least one of the clock rate charts is operating then play the game. When you hit that magic moment of heavy FPS drop go look at what the clock rate chart is showing, if its been pegged at the top and is now middling or anywhere but what the full performance clock rate is supposed to be: Suffering from same thing.

Edit: I also wanted to add that for me this condition persisted through to even playing other games, only a reboot would let the cards go back to operating at full ability. This was when I was using a trio of GTX280s but still the 290.53 beta driver.