Thought I'd give an update on this since this was part of a discussion of what computer build to use. I was able to free up this older PC to test with HQPlayer. It's an old build from last year, and was designed as a multi-GPU system for CUDA. For this test, I left it with a single Gigabyte 780ti. The rest of the build is pretty standard: Asus motherboard, I7 4790K four core CPU, 16GB of RAM, and a 1GB SSD.
HQPlayer seems to be quite happy at quad DSD, poly-sinc-xtr-mp-2s/ASDM7. I have CUDA offload enabled, Multi-core set to grey, and using Convolution and upscaling 44/24 content to 44.1x512 DSD. Here's what the CPU utilization looks like:
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19%-21% overall utilization, with all cores but one under 30%, and most under 20%. CPU temperature at 45deg C, fans on lowest setting. Unlike the Macbook Pro with the same settings, this PC makes zero fan noise that I can hear from my listening position
Interestingly, if I disable CUDA offload in HQP, the CPU utilization doesn't go up by much (hovers around 24-25%), so I don't think the CUDA offload is all that effective in this setup. I do see the load on the GPU when it is enabled, so I know it's working, but the reduction of the load on the CPU is only a few percent, so it's probably not worth using the GPU.