Router Losing(?) 25-30% Bandwidth

[OriginalCactus]

Hi all,

Running RT-AC86U with Merliln 386.2_6. It is connected to a FiOS ONT over a gigabit ethernet port for a 500/500 connection. When I run spdMerlin or the included Ookla speedtest from the router (in Adpt QoS -> Internet Speed), I consistently end up with a max 350 mbps download and only a little faster on the upload. When I take the WAN ethernet cable out of the router and connect my computer directly to the ONT (bypass the router), I see 500+ mbps down. What should I check on my router to figure out what's shaving nearly 30% off my bandwidth throughput? Or how should I have it set up? I've already turned off Adaptive QoS, shut down VPN servers, turned off AI Protection, and tried a few other things suggested on the boards. I'm just at a loss.
Screenshots of relevant info below.

Thanks!

 

[ColinTaylor]

Running RT-AC86U with Merliln 386.2_6. It is connected to a FiOS ONT over a gigabit ethernet port for a 500/500 connection. When I run spdMerlin or the included Ookla speedtest from the router (in Adpt QoS -> Internet Speed), I consistently end up with a max 350 mbps download and only a little faster on the upload.

This is a known limitation of the speed test on that model. Ignore it and just use speed tests on your PC. Your router is working fine.

 

[OriginalCactus]

Just checked and can confirm, plugged directly into the router the speeds on the computer are fine. I did not know that the router-based speed tests were always that much slower. Here is what my 500/500 looks like from the wired connection to the computer. Thanks.

 

[Tech9]

I did not know that the router-based speed tests were always that much slower.

Limited by CPU processing speed. For AC86U 330-350Mbps sounds about right.