(In reply to comment #75)
> Created attachment 90667 [details]
> possible fix
> 
> Sounds like both are causing problems.

Since my last cold boot, I tried with unlimited clocks (reverted previous
patches) with hangs almost at start. I tried again with stock 3.13-rc3 with
spread spectrum disabled, and I also hit hangs when testing (without having to
push the video card with heavy tests). So, for me, disabling spread spectrum
may sometimes help, but it is not a real solution to this bug.

Sorry for bringing bad news.