Wifi speed suddenly tanked with no changes.

[FoxPCs]

My wifi has been stable at 144mbps on 2.4g and 650mbps on 5g for several years with a netgear ac1750 n6400 router, but has suddenly started to tank down to 5mbps with about 15 minutes of the router being powered on and staying there with absolutely no changes to the network. My ISP ( cascade networks fiber optic) told my it was my router since their service either works or doesnt so I bought a new ac1750 n6400v2 and am having the same issue, does anyone know what could be happening?

[nick name]

Perhaps someone installed a competing network.  You can find mobile apps to scan wifi channels and some routers will do it too.  Have you tried to see if another network is competing with yours on the same channels?

[Donut417]

7 hours ago, FoxPCs said:

absolutely no changes to the network.

As mentioned above, doesnt matter if its a change to your network or not, a change happen in the airwaves. My guessing is an AP was setup close enough to cause issues. Best course of action is to figure out which wireless channels are free from traffic and try to use those.