My MacBook Pro 2018 has two GPUs: AMD Radeon Pro 555X and Intel(R) UHD Graphics 630. I supposed the AMD 555X would be superior in performance compared to the Intel(R) UHD Graphics 630. However, I observed a huge performance difference for Metal Performance Shaders (MPS) between the two GPUs. The Intel GPU performs the simple test code (a… Show more
Yes, the integrated GPU will be much faster for this. It's because it's a quite light workload but involves a block of memory. The iGPU can work directly from system memory, while the dGPU has to copy to VRAM, do the work, then copy back. The processing is much faster but copying across the PCI bus takes enough time for it to be slower overall.