Possible due a known issue when USB 3.0 is enabled, that the 3.0 caused some sort of interference problems with the 2.4ghz radio or the radio was causing problems with the 3.0 channel when enabled. I think it was due to the closeness of the radio near the USB chip which may have been effecting good operation. I saw a report on this from Intel about this interference when using 3.0 on some routers during this time frame. So I think D-Link decided to add the switch. This maybe why you seeing problems when 3.0 is enabled. If it works with 2.0, then run in this mode and test and see how it works out. One test you could try, disable the 2.4Ghz radio or both WiFi radios and then enable 3.0 and test. See that happens...