Slow download speeds wired and wireless Orbi 753

[sean10780]

I have really slow download speeds on my Orbi 753 i just purchased from Costco. I am running firmware V3.2.16.6_1.4.4. I have att fiber running on a pace 5268AC. I have all the router components disabled on the ATT modem and the orbi 753 set as a DMZ plus device. If i turn the Orbi 753 into an AP mode and use my old RBK53 as the router then everything works fine. I even went back to Costco and exchanged it for a new one so there seems to be something wrong with the router and my internet. Can someone help?

[FURRYe38]

Seen other posters taking about the PACE modem being a cause of some problems. 

https://community.netgear.com/t5/Orbi/Installing-Orbi-behind-ATT-Pace-5268AC-gateway/td-p/1234191
https://community.netgear.com/t5/Orbi/Netgear-Orbi-and-ATT-Pace-5268-Router/m-p/1786833/highlight/tr...

What happens with the modem in router mode and the RBR in wired mode and no DMZ on the modem?

[sean10780]

So if I have the 753 in router mode and get an ip from RBK53 who is serving as my DHCP then I'm still getting the slowdown speed. If I put the 753 in AP mode and static an IP from the RBK53, then the speeds go back to normal.

Right now I have my RBK53 in router mode and ATT Modem in DMZ pass through mode with firewall disabled and the WAN port shown in the RBK53 and it works great. If I replace this existing RBK53 with the 753 AX then the speeds are slow. 

How can the RBK53 work and the 753 not?

[FURRYe38]

Try a factory reset on the 7 series behind the ISP Modem and walk thru the setup wizard. Don't enable Armor, QoS speedtest or traffic meter. Go right in and use a wired PC and speed test with Ooklas installable speed test app. If this still fails, either return the Orbi AX for another or make contact with NG support.