ASUS RT-N66U bandwidth overhead.

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New Around Here
I am using the google speed test to assess each device on my network. All connections are ethernet CAT 6 cable.

When connected to the WAN device with an ethernet cable I get consistently about 200Mbps/sec down and 250Mbps/sec up, latency ~5ms.

When I connect the WAN device to the ASUS router WAN port, and run the test connected to one of the LAN ports on the ASUS
the results are a) lower, and b) much more variable, 15-100down/60-90up/6msec. The down number sometimes drops to 7Mbps/sec

I've looked at the logs, and I don't see anything that leaps out.

Are there any settings I need to look at on the ASUS? Any pointers much appreciated.

I have QoS-Traditional enabled, and I use for DNS.

I am on the latest official firmware (v.


Part of the Furniture
Disable QoS. The RT-N66U isn't powerful enough to run it at speeds above 100 Mbps.

P.S. I find that Google's speed test isn't remotely accurate. Verify your results against Ookla and nPerf.
Last edited:


Very Senior Member
I find Google's tests to be just fine and dandy....assuming you are a Google customer. I would for sure use a couple of different test sites and devices if you are really trying to get a clear picture of the performance.

I do agree on the N66 not being powerful enough to handle the speeds you have/want along with QoS. That is quite an old device with a not so powerful CPU.

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