Here is a test case run by someone at the CFD-online forums:
So I was eager to buy a graphics card for $120 (GTX 550 Ti) and install OpenFOAM 1.6-ext, since Cufflink only works on 1.6-ext (I have been using 1.5-dev). There are quite a bit of differences, but it did not take me long to figure it out. The biggest difference is that 1.5-dev's GGI implementation uses PISO, and 1.6-ext uses PIMPLE. I could only get stability using smoothSolver for the turbulence quantities when using the kOmegaSST model (I only used smoothSolver in 1.5-dev as well because it was the only parallel-compatible solver I think, which may still be the case here...).
Looking forward to using the cutting-edge in software and computational power. Thanks to all the open source CUDA developers.