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The Mac chips only have a couple more GPU cores than CPU cores, while discrete graphics cards have hundreds or even thousands of cores. If the benefits of train

by elil17 3y ago

The Mac chips only have a couple more GPU cores than CPU cores, while discrete graphics cards have hundreds or even thousands of cores. If the benefits of training on a GPU come from massive parallelization, why would a GPU with relatively few cores be expected to provide a benefit vs. CPU? Am I misunderstanding something about what a Mac GPU "core" is?

hnuser123456 3y ago
The M1 integrates an Apple designed[17] eight-core (seven in some base models) graphics processing unit (GPU). Each GPU core is split into 16 Execution Units, which each contain eight Arithmetic Logic Units (ALUs). In total, the M1 GPU contains up to 128 Execution units or 1024 ALUs https://en.wikipedia.org/wiki/Apple_M1#:~:text=The%20M1%20integrates%20an%20Apple,Arithmetic%20Logic%20Units%20(ALUs) https://en.wikipedia.org/wiki/Apple_M1#:~:text=The%20M1%20in.... I'm guessing when you see NVidia/AMD "cores"/"shaders", they're counting ALUs, whereas an Apple GPU "core" is just a "block of GPU" that can be copy/pasted more times to increase performance. I think NVidia has "shader modules"/SMs which are blocks of X number of "cores"/ALUs. I'm being very imprecise but I think that's what's going on.
pavlov 3y ago
Yes, I think Apple’s definition of a core is quite different from, say, NVidia’s. From Wikipedia: “The M1 integrates an Apple designed eight-core (seven in some base models) graphics processing unit (GPU). Each GPU core is split into 16 Execution Units, which each contain eight Arithmetic Logic Units (ALUs). In total, the M1 GPU contains up to 128 Execution units or 1024 ALUs, which Apple says can execute up to 24,576 threads simultaneously and which have a maximum floating point (FP32) performance of 2.6 TFLOPs.” NVidia has its own terminology. For example a 1080 GTX GPU has 20 stream multiprocessors (SM), each containing 128 cores, each of which supports 16 threads. That makes 40,960 threads which is more than the M1 GPU at 24,576 threads, but not massively so.
- elil17 3y ago
  Thank you, this makes so much more sense to me.

by elil17 3y ago

hnuser123456 3y ago

The M1 integrates an Apple designed[17] eight-core (seven in some base models) graphics processing unit (GPU). Each GPU core is split into 16 Execution Units, which each contain eight Arithmetic Logic Units (ALUs). In total, the M1 GPU contains up to 128 Execution units or 1024 ALUs https://en.wikipedia.org/wiki/Apple_M1#:~:text=The%20M1%20integrates%20an%20Apple,Arithmetic%20Logic%20Units%20(ALUs) https://en.wikipedia.org/wiki/Apple_M1#:~:text=The%20M1%20in.... I'm guessing when you see NVidia/AMD "cores"/"shaders", they're counting ALUs, whereas an Apple GPU "core" is just a "block of GPU" that can be copy/pasted more times to increase performance. I think NVidia has "shader modules"/SMs which are blocks of X number of "cores"/ALUs. I'm being very imprecise but I think that's what's going on.

pavlov 3y ago

Yes, I think Apple’s definition of a core is quite different from, say, NVidia’s. From Wikipedia: “The M1 integrates an Apple designed eight-core (seven in some base models) graphics processing unit (GPU). Each GPU core is split into 16 Execution Units, which each contain eight Arithmetic Logic Units (ALUs). In total, the M1 GPU contains up to 128 Execution units or 1024 ALUs, which Apple says can execute up to 24,576 threads simultaneously and which have a maximum floating point (FP32) performance of 2.6 TFLOPs.” NVidia has its own terminology. For example a 1080 GTX GPU has 20 stream multiprocessors (SM), each containing 128 cores, each of which supports 16 threads. That makes 40,960 threads which is more than the M1 GPU at 24,576 threads, but not massively so.

elil17 3y ago
Thank you, this makes so much more sense to me.