RB951G-2HnD PPPoE Packet loss

Hi!
I have a huge problem with packets loss via PPPoE connection with my ISP. Loss 20-40%.

Device: RB951G-2HnD
OS version: 6.19
ISP: Rostelecom
ISP connected to port 1 100 Mbit duplex.

I’ve tried to change MTU size & flow control. Nothing helped.

When connecting RB951G via Dlink DGS-1005d (1Gb switch) to ISP there no packets loss.
Direct connection from two laptops with Ubuntu all fine.

How to fix this issue with RB951G?

While I waited approve…
I found that it’s problem with ethernet 100 Mbit speed.
Mikrotik wan’t work on 100Mbit AutoNeg. And manual port speed FD/HD on both sides.

More here http://forum.mikrotik.com/t/rb951g-2hnd-ethernet-100mbps-speed-problem/81243/1

do you sure that MSS clam was still okay and enabled in firewall ? if isn’t - create one, btw.