> I assumed it was because with newer intel CPUs the PCI bridge moved to the die, away from the motherboard, so there was CPU affinity for the GPU. Actually, t

> I assumed it was because with newer intel CPUs the PCI bridge moved to the die, away from the motherboard, so there was CPU affinity for the GPU. Actually, the PCIe controller doesn't even have to be on-die. The same issue existed in earlier systems where PCIe was in the northbridge, which was attached to the first socket. Sometimes other sockets had their own NBs and own PCI buses too and things were even more interesting. I heard years ago about people pinning their GPU-accelerated applications to the "right" CPUs.