Thanks for this information. If I set N only mode to 2.4G, should I set AC only on 5G? As of now, it uses the A Standard. Of course, it will be experimental but I'd like to hear your opinion.

The router supports dual band hence it supports 802.11n @ 300Mbps and 802.11ac @ 867Mbps. However, I use 5G band for gaming and sad to say WMM affects the traffic for it. I have disabled WMM for both...