To be specific, what PS3 gamers have noticed is a direct relationship between the increasing size of the save file, and the amount of playtime before the frame rate drops. Imagine a chart, if you will. As the size of the save file increases, the amount of gameplay time before the game becomes choppy decreases. To the point where once you exceed 9MB, the game becomes unplayable after a very short time of playing. I can confirm these claims as I have experienced it now myself. I now cannot play Skyrim at all until this patch is released. This frame rate drop did not occur when the save file was smaller (less than 5 MB). All of the claims on this board are consistent with eachother, so there is no reason to not think the cause of all this is the increasing save file.
First, correlation does not imply Causation.
Second, I've read most of these threads, and very rarely does anyone articulate the issues they're experiencing. Most of what I see is this: "You've got lag too? So do I!"
That may be true across the board, but it's not helpful in identifying the problem.
Here's a couple of things to think about:
gamesas recommended that 360 users do not install to hdd, but let content stream off optical disc. PS3 users do not have that choice. Install is the only option. PS3 users are complaining of "lag", 360 users are not. Ergo, issues may be cache or streaming related, not save-game related.
Without extremely specific descriptions of the issues, you don't really know if you're experiencing the same issue as someone else. Your definition of lag may be framerate, while someone else's my be load time.
As for all of the claims on this board are consistent with each other, that's hardly surprising, especially when they're so vague. Read this:
http://en.wikipedia.org/wiki/Seattle_Windshield_Pitting_Epidemic
You yourself claim that your game is "unplayable." Do you mean that you are literally unable to play the game, or is it slightly more subjective?
Does it happen during a melee fight or when you're running around in the wilderness? Does it happen indoors? What specifically is going on during unplayable conditions?