Hi there, I post this in case this can help someone. I′ve been suffering random ctds since I started playing skyrim. I′ve tried many things: I have followed STEP instructions regarding installation and mods. I have loaded my mods one by one, using BOSS to sort the load order. I have bought a new GPU. Still my game crashed. A few days ago I found a post where someone said that he or she had solved the ctd problem by lowering the texture option from high to medium. I tried that. And it worked. I had located a place and moment where my game would crash 8 in 10 times when trying to fast travel form Windhelm to Riften. After lowering the texture quality in the options menu, no crashes at all!!
Now comes the amazing thing. Of course it′s painful having to play with ugly medium textures after having spent some good money in a new GPU, so I decided to give the HD DLC a try, although I was sure it wouldn′t work cause I only have 3Gb RAM. But it worked. I have been playing for several hours and i only have ctded once when fighting a dragon. To go on pushing things, I have installed the 2048px version of the serious HD retexture mod instead of the 1024px version I was using. I have lost some fps, but the game is still nicely playable. So the next thing I′m gonna try is to use the 2048px version of every texture mod that I use so I can compensate for the lack of quality in the textures option.
My rig:
Core Quad Q8200
3Gb RAM
GTX 650 ti

I hope this can help.

I′d also like someone to explain me why is it possible to use HD DLC and mods if I only have 3GB RAM, and I′d like to know if this can stress the GPU and break it down. Thanks

TESV.exe is a 32 bits executable and 32 bits executables cannot use more than 2 gb of ram.