As per CodilX, I am having the same problem I have ran exactly the same commands on my laptop which is an Acer Gemstone 7720G with an Nvidia GeForce 8600M GT graphix card and still this issue persists.
For me it's the intel-agp that's causing the problem and I have successfully replicated the bug/fault as per CodliX commands. So I doubt this is issolated to the ATI.
Has anyone managed to find a fix for this?
muts could you possibly comment on this?