WAC124 router - Massive packet loss only on 5GHz Wi-Fi

Hi all,

My Essentials Wireless (WAC124) #WAC124 router is about 4 months out of warranty. When connected to its 5GHz network and using real-time connectivity apps like online games, I'm having a huge amount of packet loss. Looking at the connection with Wireshark/npcap while playing a game shows that UDP packets aren't making it through most of the time, a lot of data is missing. As a test, I tried constantly pinging the game server in the background while the game is lagging, and almost all of the ping packets are coming back with the expected latency (~40ms) except for a very occasional timeout. Meanwhile, the game has 5+ second stretches where it receives no data at all

Connecting to the router with Ethernet and disabling 5GHz Wi-Fi both fix the issue.

I have tried:

• Factory resetting and setting up everything from scratch
• Moving the router
• Sitting the computer right next to the router
• Using the same computer and game on a different 5GHz connection (no issues at all)

Any suggestions? I attached a screenshot of my 5GHz settings from the web interface (switched off right now to force everything to 2.4GHz).