Mikrotik periodically cuts speed. What to do?

Question

Mikrotik

Good afternoon.
There is Mikrotik CRS125. For existing reasons, the switch is used as a router. In bridge mode, the network is 192.168.8.0 + two networks with FastPath: 192.168.0.0/24 and 192.168.7.0/24. A NAS is installed on the network 192.168.8.0. The average access speed to the NAS from the networks 192.168.0.0/24 and 192.168.7.0/24 is about 170 Mb/s. Recently, the following problem has been periodically observed: a drop in the access speed to 10-20 Mb / s. Restarting the router helps. During the slowdown, the CPU usage is 25% - 30%. CPU temperature 40-41. What could it be?

Answer 1

For existing reasons, the switch is used as a router.

Get rid of these reasons and install at least rb750gr3
PS: did you check the NAS? maybe it's a problem