Having tried many different combinations to hardware accelerate H.264 encoding using a graphics card, I’ve come to the conclusion that it is a total waste of time. Not only are the results often slower, but the quality of the encoded file is lower and the software offers much less in the way of configurable options and ease of use. In the end I will still recommend a decent CPU and Handbrake.
A particularly good and very in depth study echoes my findings - http://www.behardware.com/articles/828-27/h-264-encoding-cpu-vs-gpu-nvidia-cuda-amd-stream-intel-mediasdk-and-x264.html
“It’s difficult to provide a succinct conclusion to so many tests, but one point does stand out: GPU acceleration of H.264 transcoding isn’t on a par with encoding carried out by CPUs.”
“At the end of the day, the marketing promises in terms of GPGPU transcoding haven’t been kept. The manufacturers highlight the rapidity of their solutions as a solution to the very real problem of the excessive amount of time required for CPUs to encode video alone. By offering rapid encoding solutions, but with quality that leaves too much to be desired, H.264 encoding via GPGPU solutions remains, as yet, a poor solution to what is a real problem.”
So I’m going back to the good old CPU only encoding with an x264 implementation.