Skyrim has been getting progressivley laggier with these updates, its really been annoying for me, I never had problems with lag drops (auto detects that I can run on ultra) up until the 1.2 update, and it starts having wierd lag drops from 60 + fps to 20 fps, it doesn't change at all during 1.3, and now in 1.4, its just unbearable, going to around 15 fps, Does any one know what i can do to fix this?

windows 7 64 bit 4 gigs ram
ati 5770, asus,

Some quick questions

1) Is Vsync on? Edit: If it is off try an FPS limiter to see if makes a difference, set to 60 or 64 if you do. I say 64 due to an engine bug (Don't remember specifics on this bug).
2a) Does the FPS randomly dip to 15 or is it at a steady or consistant 15?
2b) If the dips are random to semi-random, then when do you notice them (generally)?
3) What are your shadow settings? I only ask because most games, in my experience, struggle with shadows, so might be worth it to lower them one step from their current setting to see if it makes a difference.
4) Using any mods? Texture replacers, etc? If so try removing them to see if it makes a difference.
5) Remove TESVAL of Skyboost if you still have them, as they are no longer necessary, and ENB if you have it (to see if it makes any difference)

The above is an example of my internal thought process when diagnosing problems. I would recommend trying a different driver, but that can be a mixed bag sometimes. Pauses/FPS dips could have something to do with the game clearing away the old ash piles (among other things most likely), and the game did nto do so previously.

Wierd since every single report I have read about 1.4 have praised it for increased framerates and play. Have to agree with Iriodus, the problem is elsewhere, either a system problem or mod. Your system is close to mine (win7 64, ATI 5700, Intel 7 (BTW what is your CPU?) I run on high setting with virually no probs,CTD, etc. and haven't even tried 1.4--(waitng for final.). New ATI driver came out today as well--have you kept them up to date?