Just judging by the system stats people have posted in here, it looks like the problem may be with Nvidia. If the people that posted in here could edit their posts to add their system specs (board, proc, RAM, Vid card manufacturer & model, and OS), we may be able to find the common denominators causing this.
As a note, I am getting about the same time span between lockups as Ganinos, except for me it seems to happen every 54-58 minutes. Unchecking keep maps loaded made no difference.
I am going to try playing PS on SUSE Linux. I have a SUSE installation on another drive in the same comp, so the hardware specs should be the same.
Sorry if I'm being pushy or overstepping my bounds in requesting this info, but I hate having to watch the clock so I remember to manually relog every 45 mins or so.