Hi, Okay here is the scenario, why and how can I fix it? I have a mid-2012 rMBP and 2014 riMac (both running Yosemite 10.10) and Asus RT-N66U wireless router. On my rMBP in the same location and orientation as the iMac the Wifi link speed to my router is 450Mbps, and performance is what I would expect. Signal strength is 80%. On my riMac my link speed is typically around 73Mbps, very occasionally it might hit 200 or so but that is very rare. And I get the terrible performance I would expect from this speed. Signal strength is 85% (higher than the rMBP). All things on my router are the same between the rMBP and riMac. I thought it might be the bluetooth keyboard and trackpad causing interference (which would be stupid), but the rMBP in the exact same location does not suffer with reduced Wifi speed. Thanks.