(In reply to comment #6)
> (In reply to comment #5)
> > I'm not sure, correct me if I'm wrong but Zaphod is for running seperate x
> > sessions on the same card?
> > I'm using a card per session.
> > 
> > anyway, I'll revert the patch and try, will report soon.
> 
> You are correct, but I'm wondering if that patch is causing a problem in
> your case.  You might try reverting that patch as well if the 2D tiling
> patch doesn't help.

issue confirmed, it was indeed that Zaphod patch.