It seems ever since I had my logic board replaced (I think unnecessarily) my MBA hasn't been able to connect to the wifi at the full 300mbps* speed. The router is a Linksys E3000. My 5Ghz wireless is set up with 40mhz wideband, channel 40, WPA2 AES security, WMM enabled. There are no other 5Ghz signals in my building as far as I can see. Another computer in my apartment, an aging Dell, is able to connect at 300mbps no problem. So I'm pretty sure the router is not the issue. I ran a modified version of TomatoUSB on it, but last night I reverted back to the stock Linksys firmware and I still had the same issue. Dell at 300, MBA at 150. The interesting thing is when I change the wireless settings to be narrowband at 20mhz, the Dell goes down to 150Mbps as expected, but the MBA goes down to 65. Approximately the same signal strength on both computers. The only thing I have left to do to narrow it down to the MBA is to take it to a friend's house to test it in a different environment. I am still not convinced it isn't some setting in the MBA that I am missing. Could that be it? Has anyone else experienced this odd behaviour? Prior to the repairs I linked above, I was able to connect at 300Mbps all the time. * I know that when the connection speed is 300Mbps does not mean I will get that speed in the real world. However, I move medium size files over to a NAS sometimes, and the difference between 150 and 300 in the realworld is substantial enough for me to notice and make a difference.