topic Re: Does Canon DPP4 use both GPUs on 2019 iMac with Intel CPU? in Camera Software

Does Canon DPP4 use both GPUs on 2019 iMac with Intel CPU?

johnrmoyer — Sun, 19 Mar 2023 17:00:48 GMT

Thanks in advance for answers or information that might lead to answers.

My 2019 27 inch iMac has two GPUs. MacOS 13.2.1 (22D68), also called Ventura.

CPU: Intel(R) Core(TM) i5-9600K CPU @ 3.70GHz

GPUs: Intel HD Graphics CFL + Radeon Pro 580X

The display is connected to the Radeon Pro 580x.

Is the GPU on the Intel CPU chip used for computation? Apparently I could use both GPUs in my own code developed using Apple Xcode.

Will the Canon DPP4 program use the Intel GPU for computation?

Canon DPP4 appears to me to use the Radeon GPU for display purposes according to Activity Monitor app.

Activity Monitor app does not seem to me to report on both GPUs.

Traditional Intel CPUID program: https://www.intel.com/content/www/us/en/download/674424/maccpuid.html

The CPU in my iMac: https://ark.intel.com/content/www/us/en/ark/products/134896/intel-core-i59600k-processor-9m-cache-up-to-4-60-ghz.html

Re: Does Canon DPP4 use both GPUs on 2019 iMac with Intel CPU?

shadowsports — Sun, 19 Mar 2023 22:20:45 GMT

Hi John,

This is a thread we all chimed in on from 2019.

DPP 4 on AMD Ryzen Threadripper - Canon Community

I use DxO for post and conversion, so I do not know if DPP is multithreaded or how it behaves on an intel based MAC.

Re: Does Canon DPP4 use both GPUs on 2019 iMac with Intel CPU?

johnrmoyer — Mon, 20 Mar 2023 09:34:07 GMT

Thanks.

Re: Does Canon DPP4 use both GPUs on 2019 iMac with Intel CPU?

johnrmoyer — Mon, 20 Mar 2023 10:48:00 GMT

Thanks again. I have now read the previous thread.

In answer to my own question, it appears to me that DPP 4 does not use the Intel GPU on the CPU chip but does use the AMD GPU which is on a separate chip for updating the display but not in batch mode.

It makes sense to me that the SSE and AVX instructions on the main CPU chip would be used for vector processing because when dealing with large bitmaps DRAM access is the bottleneck and the CPU chip has the fastest access to the level 3 cache. When I worked with image processing algorithms some decades ago, DRAM speed was closer to CPU speed than it is now.

All six CPU cores are used by DPP. Since processing a large bitmap is limited by access speed to main memory, I would guess that CPU cores are spending much time waiting for DRAM. The 9MB level three cache on my CPU is not large enough to hold a 45MB CR3 file from the EOS R5. Transferring that much data to and from an external GPU would take significant time so it makes sense to use the external GPU to update the display instead of for the image processing algorithms.

Thanks again.