AR8327N port 0 (CPU) low throughput

Hi,

I am hoping that you will be able to help me with this problem.
I designed a board using the AR8327N switch IC and connected an input to Port 1 and two devices to Port 0 and Port 2.
Throughput from Port 1 and Port 2 is fine and is not a problem. The problem is with Port 0 which I didn't know that it was meant as a CPU port.
There are some registers to configure ports/flow control... so if somebody can please point me in the right direction.
Right now communication through Port 0 is working but it keeps dropping (every 2 seconds for 5seconds).

I found this in MikroTik documentation that gave me some hope.

All switch chips have a special port that is called switchX-cpu, this is the CPU port for a switch chip, it is meant to forward traffic from a switch chip to the CPU, such a port is required for management traffic and for routing features. By default the switch chip ensures that this special CPU port is not congested and sends out Pause Frames when link capacity is exceeded to make sure the port is not oversaturated, this feature is called CPU Flow Control. Without this feature packets that might be crucial for routing or management purposes might get dropped.

Since RouterOS v6.43 it is possible to disable the CPU Flow Control feature on some devices that are using one of the follow switch chips: Atheros8227, QCA8337, Atheros8327, Atheros7240 or Atheros8316.

We aren't doing any configuration to the AR8327N so the registers are in default state.

Thanks for any help.