I misread the original report(s) and thought the hangs reproduced at X startup. Unfortunately, there are a variety of scenarios that can be perceived as X hangs, with a number of possible root causes, each.
Please, if you have a stability problem that you can't solve even after working through the host of suggestions made by users of these forums, send a detailed bug report to firstname.lastname@example.org
. Include any appropriate hardware and software configuration details, as well as relevant log files (XFree86/X.org, nvidia-bug-report.sh, ...).
@haimeltj: There've been several reports of SiS AGP stability problems after the release of 1.0-6106/1.0-61111, which we will investigate; since your problem reproduces with AGP disabled, this may not be applicable. Have you checked your system's memory?