1. First off, for those who still don't believe overheating is an issue, here is a link from an email I received from Bethesda:
http://s12.postimage.org/c7vrbfsp9/bethesda_email_ps3_lag.jpg
What else can you do about this besides turning your console off and waiting 15 mins or so? Not much really. Standing my PS3 vertically seemed to improve ventilation. Also make sure the room you are playing in doesn't heat up too much.
2. (credit to Grunza) in this thread: http://www.gamesas.com/index.php?/topic/1268800-stop-go-stop-go-stop-go/
Try these things if you have not already. The all capital letter words in parentheses is the setting. Follow step by step. Settings can be found in the XMB menu second from the left. This is the main menu before you start playing your game. I appologize if I have made this more complicated then it needs to be. Anything that has (HDMI) by the setting should be adjusted accordingly. Meaning if you are not using an HDMI cable to connect your playstation to your tv choose (OFF) or the most simple option. If you are connected using an HDMI Cable follow these select what I have. I am running this game very smoothly right now. Good luck and I hope I made even a slight difference in someones gameplay.
-Settings-Game Settings-PS Upscaler (OFF) PS Smoothing (OFF)
-Settings-Video Settings-BD/DVD Upscaler (OFF) BD/DVD Video Output Format (Y Pb/Cb /Pr/Cr) 1080p 24 Hz Output (OFF) BD/DVD Dynamic Range Control (OFF)
-Settings-System Settings-Display [What's New] (OFF) Notification Messages (DO NOT DISPLAY)
-Settings-Display Settings-Cross Color Reduction Filter (OFF) RGB Full Range (Limited) Y Pb/Cb Pr/Cr Super-White (OFF) Deep Color Output (OFF)
Got this advice off another thread. Credits go to Yackpah
This really improved mine. I only get a bit of lagg after 4+ hours of constant gameplay but very little if any before hand. My save file is 7mb too
to add to these suggestions, if your not worried about sound quality, try adjusting the sound settings to output only low quality sound (within reason, will not change that much if at all, and i cannot confirm any difference in frame rate)
3. Uninstall the patch. Delete the game data utility. Disconnect internet. Start game, install the game. Enable internet. Download and install patch.
I cannot confirm any difference in frame rate but thsi is what I did on my second playthrough.
4. Delete all unneccessary file saves. Turn off all auto saving in the game settings. Selling/Dropping items in inventory may decrease file save size.
I cannot confirm any difference in frame rate, but I did this on my second playthrough.
5. Probably the best thing you can do: change your video output in the ps3 settings to output a max setting of 720p even if your tv is 1080p or 1080i capable. (If your tv is not 720p capable obviously do not change this setting leave it as whatever you had it set to)
Why? Well first off, the game is actually in 720p anyway, its just that when you tell teh ps3 to output a 1080p signal when playing a 720p game, it has to upscale the image. This uses a lot of resources, and improves the picture quality, but it doesn't actually change the image to true 1080p. You will notice a difference, but it won't be that bad. IMO frame rate>graphics. MAKE SURE YOU CHANGE THIS BACK TO 1080p WHEN WATCHING MOVIES LOL
6.0 Do not shut up about this issue, send an email to Bethesda and let them know we want a patch that will at the very least fix the save game issue (large file saves that grow infinitely)
I hope this helps and that I remembered everything.