I see a lot of people coming on the forums that are having issues with the game freezing and I figured I would share what I have discovered about this issue. Long story short it has to do with modding.

Like many others my game started the infamous freeze with the music still playing in the back ground. It seemed to happen more frequently transitioning into or out of buidlings, but would still just randomly occur in the open world. There was no pattern or logic to when it was freezing and seemed completely random. for me, my freeze average was about once every 3 to 4 hours, I did have spurts of several in an hour though.

I began the usual troubleshooting of my hardware thinking something was wrong, but I couldn't find any issues with various stress tests, so I just generally put up with it. Earlier this year a built a completely new gaming system and skyrim would still freeze like my old system did. By this time I was 100% positive it wasn't hardware related.

This lead me to look back in to what I was doing with mods. I have had some troubles with mods on previous bethesda games, so I am picky on how I mod my game. I never used mods that had an ESP. In other words I was using only replacer mods, and in particular armor mesh replacers i would dump in the meshes folder and that is it. I figured since there was no esp, so no new scripts or anything like that, my save files wouldn't get borked up and cause crashes and such. I was wrong. After a couple hundred hours of play I did begin to notice a bit of a pattern. When I added a new mesh replacer, the probability of freezing increased dramatically. I found that removing or renaming my mesh folder and loading and saving the game "clean" helped. After that I would reload with my mesh replacers. I emphisize helped, as the game would still freeze, but just a lot less frequent.

I started a new game, with all my armor mesh replacers intact. This time I decided that no matter what I won't add or change any meshes that I currently have and just stick with what I have from begining to end. I put in 80 hours and not a single freeze. I started another character since and have around 140 hours of game time between the 2 characters and not one single freeze. So the conclusion, if you are constantly cycling in mods, and even simple mesh replacer mods, you are most likely going to start freezing up your game. It seems some sort of data with the meshes gets tied to your save file and starts messing things up. It also appears that if you add mods that have their own meshes and are not replacing anything(custom unique armors), they seem to be ok and won't cause problems, unless you run that mod for a while and try to replace one of the mods meshes.

There are probably other things that can cause the freeze issue, but I bet this one affects a lot of people. It's something to try out or look into.