5G WiFI band has sluggish performance onRAX43v2

[cr5720]

Connecting to 5ghz wifi band performs sluggish. Delays every 10-15 minutes, 3-7 second delays on web pages.

Switching back to the 2.4GHZ band performance is as you would expect.

After a router reboot, performance is acceptable for about 3-4 days, then the poor performance returns. Any guidance is much appreciated.

[FURRYe38]

What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz and 40 to 48 channel on 5Ghz.
Any Wifi Neighbors near by? If so, how many?

Is Smart Connect, Beamforming, MIMO, Armor, Smart Parental Controls or Circle, Traffic Meter enabled? 

What Firmware version is currently loaded?
What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?
Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended. 

Has a factory reset and setup from scratch been performed since last FW update? A complete pull of the power adapters for a period of time after the factory reset then walk thru the setup wizard and setup from scratch with a wired PC and web browser. Recommend setting the default DHCP IP address pool range to the following after applying and a factory reset: 192.168.#.100 to 192.168.#.200.
https://kb.netgear.com/24089/How-do-I-specify-the-pool-of-IP-addresses-assigned-by-my-Nighthawk-rout...