CPU hitting 100%

Just curious what can cause our Peplink 380 cpu to hit 100%? It seems to hover over 90% a lot of the time.
We have 170 users, with 3 15mb/2mb connections. We do use QOS to limit user’s individual traffic.

We have other 380s with the same configuration and user amount that lower CPU usage.

We have tried the latest firmware also, but it doesn’t help.

In this situation, I suggest to turn on Remote Assistance of the unit and create a support ticket here with mention this forum thread. Thx