I looked into that myself, but the number of cores didn't compare to that of GPUs - the cost was right, though. I don't know if those boards were better than a GPU or what? Maybe they were more optimized for compute than what a GPU is? I was kinda looking at them for playing more with ML (I've gotten tensorflow with CUDA working well on my 750 ti GPU and it wasn't bad - but the cost for something better beyond a 900 series was crazy at the time).