I have a mid-2015 5k iMac. I also have gigabit internet. When I sit my iMac right next to the router, I get 500-550 Mbps at best with wifi. With Ethernet I get 850-950. The wifi router is brand new (802.11ac) and has 3 bands. The 5G band is rated at 2166mbps and the one I connected to. This leads me to believe that my imac's wireless card is not beefy enough to handle the gigabit speed. So, my question... I have been having trouble finding the specs on the wireless card online to see what the max speed is of it. Does anyone know? And can I replace this easily?