The realtek wi-fi chip is simultaneous 150 mbps in and out. Realtek saying it's 300 is misleading. That is the best rate in lab settings. The industry needs some way of defining chips, and saying what the connecting rate is in a 1 meter distance test is how they do it. In the real world you don't get 150, you could be getting 50, or less. So copy/streaming rates of 2-3 mb/s is not unexpected. So yes, network copying will take an age, even by cable. Copying is CPU intensive, and with realtek designs the CPU is the bottleneck. Even with Gbit cable, an X3D only manages 14-16 mb/s.