Nighthawk R7000 - throttling internet connection

[cabwav]

Internet download speed is substantially lower that what I am getting from my ISP. When I connect my computer directly to the modem with a CAT7 certified cable, I get the full 400mbps that I pay for, but when I connect the same cable to the R7000 (WAN connected to the modem) I get much less (Ookla says ping 13ms, download 181 mbps, upload 41 mbps). Online gaming suffers from low and fluctuating frame rates and lag. 
What could be wrong? Any suggestions on how to solve this are much appreciated.

R7000 firmware version: V1.0.11.123_10.2.100
QOS = off, guest network = not enabled, no parental controls, A-security not enabled

OS: Windows 10

modem: ARRIS TG2492LG (bridge mode)  
 

[cabwav · Accepted solution]

The problem is solved. It turned out that I had to reset the router to factory settings. This didn't work the first time with the router lights going crazy in various repeating configurations, but after a couple of tries including resetting the modem, I finally got Ookla to report the correct download speed.
Thank you for your help

[plemans]

If you put the arris back in router mode (disable its wifi) and connect the R7000 in access point mode, does it hit full speeds? 

it wouldn't be the first device I seen not function properly in bridge mode. 

[cabwav]

Thank you for your reply. I cannot revert my modem back to 'normal' mode myself since this has to be done by my ISP. I am going to ask them to cancel the bridge mode, and I will let you know if this makes any difference. 

It still puzzles me though, since I tried connecting to the modem directly to my PC and this seemed to work perfectly with the expected speed of 400mbps. So my conclusion was that the R7000 was the culprit, and not the modem. But maybe there are other considerations that I am not aware of.

[cabwav · Accepted solution]

The problem is solved. It turned out that I had to reset the router to factory settings. This didn't work the first time with the router lights going crazy in various repeating configurations, but after a couple of tries including resetting the modem, I finally got Ookla to report the correct download speed.
Thank you for your help

[plemans]

Eitherway, glad its working again