The game has been running very slow since the major update a while back. I think some optimization of coding is in order. I know your stance on this issue is “get a new computer” but I feel even with my rig it should be running decently. I can run World of Warcraft with no problem, for instance, and it is a 3d game.
I agree, brought up this problem some while ago, and while there were no solutions for me (but for the ones having CTD issues there was a workaround) I just got used to the game having a bit more stuttering than before.