to those of you still having issues, if you haven't tried the following...give it a try. i worked for me on my toshiba L70 8.1 machine with atheros ar956x wireless adapter.
TCP/IP Stack Reset
open admin command prompt and type the following:
netsh int ip reset C:\resetlog.log
restart the computer/laptop
Disabling TCP/IP Autotuning
disable the TCP/IP autotuning. Open admin command prompt and run the following commands one by one:
netsh int tcp set heuristics disabled
netsh int tcp set global autotuninglevel=disabled
netsh int tcp set global rss=enabled