Router Speed Test vs Laptop on 1GB port

[vbphil]

I'm on  a RT-AXE7800 router, 2.5GB connection to Comcast 2.5GB (White) Modem, new model. I also have the Comcast Gigabit Internet plan (Download speed: up to 1200 Mbps, Upload speed: up to 35 Mbps). A Speed test run from the router's QoS settings section and also from a laptop connected to a GB port. The laptop used the Speedtest by Ookla application rather than from a browser.

My speed test results were:

• router 1413.87Mbps / 41.81Mbps (down/up)
• laptop: 608.42Mbps / 41.26Mbps

I guess there can be numerous reasons why the download speeds differ by so much as there's plenty of variables but before I fall into this rabbit hole of troubleshooting, I'm wondering if this is normal behavior, or could I have an issue somewhere?

[jzchen]

Try the speedtest.net website test.  I tried both just now and the website was actually (significantly) faster:  1 app speed test, 1 website speed test, (then to confirm) 1 app speed test...

[vbphil]

Didn't work for me. speedtest.net gave a download of 307.96 Mbps while the app gave 567.39 Mbps.

[jzchen]

I recently got a Dell OptiPlex 7040 refurb from my local Micro Center and installed a 10 G NIC from Amazon, (used my son's Amazon account so don't have the exact product but the box says NICGIGA).  I have 10 G backhaul (in wall wiring to and from a 10 G switch), to an AXE16000 which is our router.  Similar to you the WAN port is 2.5 G and modem port is 2.5 G, but we pay for 1 Gig service, which from experience is provisioned around 1077/1078 max, at least per router's GUI speed test.  Yesterday I was able to get 1111 Mbps but dumbly didn't take a screenshot, via the speedtest.net website.  I haven't bothered downloading the app...

Highest this morning is 1085, as background when I log into the router ASUSwrt (webGUI) I have never seen anything above 1078.

The AXE11000, my previous router, is provisioned similarly to the AXE7800 with respect to ethernet port speed.  I can say that given 1078 speed connected to that router's 1 G WAN port router speed testing maxed in the high 97x Mbps range.  I wouldn't expect more than that.  Have you tried WiFi speed testing?

[vbphil]

I'm getting 404 Mbps on 5GHz WiFi and 132 on 2.4GHz both times at about 7 feet from the router. I'm also getting around 350 Mbps on 6E WiFi  with the Amazon Fire Cube which is about 30 feet from the router across the room.

You say you got 1111 Mbps using Speedtest.net. Was that using a 1GB port and  Network Adapter (oh wait, I just realized you have a 10Gig Adapter)? Curious what Speedtest server you were connected to. I should be able to do the same(Well maybe not, I have a 1 GB adapter) but getting choked somewhere. I played around with QoS settings on the router but was only able to choke it more but never speed it up to my laptop.

[jzchen]

Yes 10 G PCI-e NIC, so 10 G backhaul.  (The AXE7800 is new I hope it works well for you.  I have a different router I’m afraid).

Frontier server Giggle Fiber is our service. (It’s a local company that services only two cities here in SoCal).  With 1 G ports I suspect you should be able to get 97x Mbps…

[Rooke]

There might be a difference between the buffer sizes that the router and Windows are using that might explain the difference.  I suspect the router is using the maximum buffer sizes for the Receive and Transmit buffers, and Windows is using the default buffer sizes. 

You can easily change the buffer sizes for the Windows Network adapters:
1) Right-click the Start Menu and select Device Manager.
2) Open the tree for Network adapters and right-click your adapter; Select Properties.
3) Click the Advanced tab.
4) Scroll down to Receive Buffers; Select it and change the Value to 2048 - the max value.
5) Scroll down to Transmit Buffers; Select it and change the Value to 2048 - the max value.
6) The changes should be immediate, but reboot Windows to make sure the changes take.
7) Run your tests again.

I've personally done this for every version of Windows and every new motherboard and additional NIC I've installed, and I consistently get the max or better (+5-10%) rated speed for my ISP connections through Windows.

The only downside to increasing the buffer sizes on Windows is slightly increased memory usage.  But if you have 8GB or more memory, it's trivial.

[vbphil]

@Rooke - Funny you should say that. I found that earlier thru a web search and so increased both buffers to the max at 2048 but it didn't help. I also tried connecting directly to my modem thus elliminating the router from the equation but I was still only getting around 600 Mbps. My conclusion so far is maybe the router's speed test is not accurate or something's still amiss with my laptop. One thing to consider about the router is that it measures around 1400 Mbps download while my service plan is the Gigabit, supposedly a max of 1200 Mbps.

[vbphil]

I resloved the issue on my laptop. Turns out it was a piece of software, AdGuard. I uninstalled it and I'm now measuring 947.47 Mbps using the Speedtest application. I'm still doubting that the ASUS RT-AXE7800 speedtest is accurate. Comcast says my network service is 1200 Mbps max so when the router measures 1412.85 Mbps it isn't correct. I can't imagine Comcast would give me more than I'm paying for.

[Rooke]

Glad you found out what was causing the problem.  As for the router's speedtest, I wouldn't be surprised if Asus' internal test "juiced" the speeds to make their product look better. That's not the 1st time a vendor has done that.  And probably not the last. 
It's not fair to the consumer for a vendor to try to con them into thinking they're getting something they're not.