Zyxel NR5101 download speeds vary too much

Hi everyone,

Just got this model to try to compare with the ZTE MC801A.

Honestly the Zyxel it is far better when it comes to download and upload speed. Ping is a bit higher, unfortunately.

However, I'm facing a random problem. Normally I can get up to 400 Mbps download and up to 90 Mbps up.

However, randomly, at some point in time the router only gives me single digits download while remaining to give me at least 60 Mbps upload.

After a while I get again very high speeds download and upload. Sometimes I get very low values on one device and very good values on a device sitting right next to it (not testing at the same time).

I am convinced this is not the modem/5g connection but have no clue what it might be. I had the theory it could be some "savings" mode of the router, but I can't find anything in the settings.

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Does anyone have a clue here? Would love to keep the Zyxel but the ZTE has proven more reliable so far.

I'm on the latest v5 software and had version 6 installed before.

Both my 2.4Ghz and 5Ghz are using the same ssid but I can confirm the devices I test from are connected to 5Ghz.