cpu

In QC, go into preferences whilst holding down alt, go to system section, tick 'QCDisableCLOpenGLSharing'.

Thats it really, reload QC and compositions that use openCL will now run on the CPU. It appears to work across the system, eg my itunes visualizer that uses 2D Fluid Simulation now works on my mac pro.

This trick can also be used on systems that do have a functioning OpenCL GPU, but you want to see how your CPU performs, because QC will now use your CPU instead (you can check this using the Context patch but it will be pretty obvious from high CPU use.)

Hope this is of use to some of you whilst waiting for Apple to fix bug or convince spouse that new computer is a good idea ;)