Unless its your TV that's running slow, may have been better to put this with the Broadband Treads instead of TV issues.
Try a pinhole reset to force any updates. Press and hold reset button on back for 15 seconds then release for 5. Repeat this 3 times and wait 10 mins for it to load back up.
Log into GUI by typing 192.168.0.1 into a web browser then go to
-Advanced Settings > Wireless > Wireless Signal
1 make sure 2.4 and 5 are enabled,
2 scroll to bottom and disable smart wifi,
3 select 20/80 on 2.4GHz and 20/40/80 on 5GHz
Save settings
(Wi-Fi will drop out and then re connect)
re enable smart wifi and save settings again