Hi, hopefully someone can point me in the right direction...

I currently have a Fritzbox 7530 connected to my ONT and have my two Deco M9 Plus units. One is directly connected to the Fritzbox and the other is wireless.

I am trying to remove the Fritzbox middle man so that my ONT connects directly to the Deco however when I do so my internet speed considerably drops and im not sure why.

When i have this setup:

ONT -> Fritzbox -> Deco 

I get a nice 700mb+ download and upload speed

When I have this:
ONT -> Deco

I get under 100mb download and a 300mb upload

I have no idea why this is happening. I am using new Ethernet cables and have swopped them over just to make sure.

I am setting up my Zen provider details a PPPoE and enabling VLAN with the ID being 911, the Priority as 7 and 802.1Q Tag as enabled.

Any help or suggestions would be greatly appreciated.

Thanks in advance.