Installed 384.3 on my AC68U (upgraded from 380.69_2) and even after performing a factory reset I think I'm seeing some lag on both 2.4 and 5 GHz compared to the older generation (Apple devices mostly).
Moreover, my desktop computer running Windows that has Asus PCE N-53 wireless card installed is suddenly unable to play an IPTV stream in HD without stuttering. There's a significant lag in browsing websites as well. It takes a ton of time between entering an address then hitting enter and getting the actual website to load. Lag + throughput went down significantly it seems.
Now, given that this wireless card has been problematic ever since I bought it (causing BSOD during Windows installation, not seeing some 5 GHz channels at all), I'm wondering if it's about time to put it in the trash and buy a new one or the problems can be possibly related to the firmware? I've reverted to 380.69_2 and all good again.
I'm located in Europe (router is configured for the DE region). There is a ton of 2.4 networks in my neighborhood but no 5 GHz besides mine. I use pretty much the default factory settings with no significant changes:
Adaptive QoS: on, prioritize media, voip, games, web, files, other in the respective order.
Lan -> IPTV: Enable multicast routing and efficient multicast routing
WLAN -> Professional: Enable IGMP snooping
Tools -> Other: Stealth mode on
Happy to provide more info if necessary