I would say that CUDA is part of their speed problem. My company has been doing GPU programming for years and we often get 100X-300X+ speedup over the CPU, but

I would say that CUDA is part of their speed problem. My company has been doing GPU programming for years and we often get 100X-300X+ speedup over the CPU, but we do almost all of our GPU work in shaders. CUDA/OpenCL is much nicer to deal with, since not all problems map nicely to pixel/vertex shaders, but we've tended to have a very difficult time getting CUDA to go from "it's working" to "wow, that's fast". Luckily, in our space most operations map well onto shaders.