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> I thought the advantage of the GPU is not speed but parallelism or are modern power saving processors also slow compared to GPUs on non-parallel tasks? Fast
by dahart 5y ago
> I thought the advantage of the GPU is not speed but parallelism or are modern power saving processors also slow compared to GPUs on non-parallel tasks?
Fast and parallel are two ways to say the same thing, or in other words, the wide parallelism of the GPU's many math cores is what makes it faster than CPU's relatively small capability to do math in parallel. (The x-factor is so large, the power saving features don't really make a meaningful difference.) The tradeoff is you need a highly parallel workload to be efficient and that much faster on the GPU.
- foota 5y agoI think they're actually asking, if you have a single "thread" of a GPU, is that one thread quicker at math than a single thread of a CPU? The most fair comparison imo might be a single "warp" in nvidia terms against a single CPU thread, which is roughly similar to what a CPU might be doing for AVX.
- stephen999 5y agoIt’s much slower. GPU single thread performance is very slow. Unless you are doing some specialized operation that has a special instruction on GPU, it will be slower. GPU clock speeds are lower in general and the CPU has a much wider super scalar pipeline. Can be 4-8 wide vs single or double wide for most GPUs. It also has many latency-hiding techniques for a single thread. The GPU has none, it uses multiple threads to hide latency.