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Sep 17, 2022Liked by Laszlo Sragner

Is moving compute to a GPU really greener? Is there any study about that?

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GPUs are 10x more efficent. 100x faster, 10x more energy consumption (very rough back of the envelope calc)

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Sep 18, 2022Liked by Laszlo Sragner

Interesting, I did not know that. So I did some search for studies. Here is a 2018 study that finds GPUs indeed use less energy than multithreaded CPUs for algorithmic problems they are suited to solve (but can be much worse for generic problems, which probably expected). Though the benefit seems to be significantly less than a whole order of magnitude “more green”. http://portal.amelica.org/ameli/jatsRepo/30/308008/html/

Plus, note that it seems that GPU energy efficiency has been stagnant over the last decade or even getting worse, while CPU efficiency has been increasing. https://en.m.wikipedia.org/wiki/Performance_per_watt (see “GPU efficiency“).

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GPUs are near exclusively used for the purpose they are created for. The TOP500's machines do contain GPUs in the nodes so some of the FLOP/Watt improvement is due to the overall performance increase.

I do know that GPU usage is optimised at maximum power consumption (we did a project benchmarking a new supercomputer).

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