I think it's more accurate to say that PCIe link bandwidth matters when your VRAM capacity starts to become insufficient, a problem that Apple sidesteps. The ke

I think it's more accurate to say that PCIe link bandwidth matters when your VRAM capacity starts to become insufficient, a problem that Apple sidesteps. The key advantage of Apple's unified memory strategy isn't fast communication between CPU and GPU, but in granting the GPU access to a high-capacity memory pool (with some side benefits of giving the CPU access to GPU-like memory bandwidth).