AC1200 Model A6150 connection speeds

I purchased a model A6150 about 4 months ago.  It worked great at first but the last month or so the connection speed will be very slow (speed test about 1mbps).  I unplug it from the usb port for a few seconds the plug it back in and works fine (speed test 93 mbps).  Have to do this a least once a day sometimes a few times a day. I did register it when I bought it but no longer have the reciept.  Is there anything I can do other then buying a new adaptor.  I have downloaded the latest driver.

Thanks for any help.

Don