I had my upgrade last weekend, from 300 to 500mbps. However after the upgrade, i couldnt even get back my previous max speed using 5ghz, nothing has been changed in the setting. At last, i changed the width in 5ghz to 20/40/80 (was 20/40)only i could get 450 and above but not everytime (better than when 20/40, i can only get max of 330+ using 5ghz), i also fixed the wifi channel for 5ghz now. Still monitoring the performance.

But am still concern what is the root cause that i cannot get the previous max speed after the upgrade since nth has changed in the setting?