now I can see that OpenCL for Kepler was broken in 10.8.2 and has been fixed in 10.8.3. http://www.tonymacx86.com/343-os-x-10-8-3-nvidia-6xx-opencl-benchmarks.html
In this reason is it better to choose the GTX 650 ti (or to wait for GTX 650 Ti Boost (24 ROPs, 980/1033 MHz, 6.008GHz GDDR5, 192-bit))?