Here's some previous discussion: https://news.ycombinator.com/item?id=4702456 https://news.ycombinator.com/item?id=4702456 In terms of raw GFLOPS, you shouldn

Here's some previous discussion: https://news.ycombinator.com/item?id=4702456 https://news.ycombinator.com/item?id=4702456 In terms of raw GFLOPS, you shouldn't. Parallela offers something halfway between a multi-CPU cluster, differing in terms of memory access, and a GPU, differing in that each core is a real core and can be independently making calls, branching, etc. Another point to note is that every GPU architecture is different and that some support a different degree of control flow parallelism vs. data parallelism. Ultimately it depends on the kernel you're working with - if you're to a point where you've got strictly linear SIMD and you depend entirely on floating-point math throughput or memory bandwidth, it wouldn't make sense not to use a GPU instead.