there was/is some performance regression in OpenCL driver on nVidia site. also Geforce 680 and other chips from this family is crap for GPGPU. nVidia strip down every feature which is not needed for DX/OGL rendering and it is not driver/SW limited. nVidia will bring two different GPUs. one for gaming purpose and second for Tesla GPGPU purpose. on other hand new Northern Island aka Radeon 7xxx chips are huge improvement for GPGPU on AMD side.
Originally Posted by zeealpal