Why is the speed of routing on Mikrotik very low?

Question

Mikrotik

Greetings experts.
We have the device RB951G-2HnD
A. There is a main network of the enterprise 192.168.1.0/24. Interface 2.
B. Access to the global from the provider via PPPOE. Interface 1.
C. Branch network 192.168.1.0/24, PPTP connection through the same router.
D. Remote network segment behind radio bridge 192.168.3.0/24. Interface 3.
The router is configured with a PPPoE client for the provider, PPTP for the remote branch. NAT from our two networks (but not the branch network) to the ISP. Between our networks, the exchange is driven by IP routes.
CPU usage is consistently low with no spikes.
The actual problem is that the speed from the main network A to the machines on the network behind the radio bridge D is a miserable 13-15 Mb / s, although if you connect the link to this network instead of a router to a laptop and measure the speed to points - 35-45 Mb / s . I measure iperf.
I can’t believe that the power of the router is not enough to push through such ridiculous speeds. Maybe someone has an idea where I could screw up when setting up?

Answer 1

Nothing comes to mind. Show all config.