Hi Hamish, well that's all pretty baffling.

The main thing that's particularly weird is that there haven't been a whole lot of changes in the display mechanism (other than the multi-threading which you already disabled) from v2 to v3, so I don't really understand why only recent v3 betas would show this problem for you...

Is there any possibility that your video card is overheating? If you don't have any method set up to measure that you might try using a monitoring app (here's one: http://www.cpuid.com/softwares/hwmonitor.html) to see if the temperatures are creeping up while the 3D graphics functions of your card are in use. Also if your machine is clogged up with dust that would be good to vacuum out and if it has gotten pushed up close to a wall maybe it needs more space to get better airflow through it.

But if those were the case I would really expect to see v2 behaving like that as well, I don't understand why you would only see this on v3.

- Michael