HP 2915 why speed slows down between vlan?

Question

Network routing

Good afternoon, I ask for help in resolving the issue.
There is a network in the region of 70 PCs. The network is divided into specific vlan, for data, management, IP telephony.
When you enter this router into the network in the mode of the main router, routing according to the rules between vlan, at first there are no problems, but after a while there is a failure in network speed, loss of pings between vlan, problems with IP telephony (due to slow speed and packet loss).
The switch's CPU load is above 50 percent. Clearing the arp cache does not solve the problem. It is treated with a reboot, but after that everything repeats.
At the moment, this routing between networks is temporarily performed by mikrotik 951
, there are no problems.
The description for the switch says its memory for 8k addresses.
What could be the problem with this switch?

Answer 1

Routing to the Internet is also carried out through this machine? Are there any bells and whistles like Kerio Win Route or other routers on the network?