Speedtest - Half speed from Lan

[snbdora]

Hello,

I've an internet connection of 1G/350Mbps from ISP. The speed test from ASUS TUF-AX4200 UI show 1G/47Mbps ( Modem I've is S33v3 which supports ~ 47Mbps upload only ) which is fine. However, when I do a speed test from Lan,
I get about 400-500Mbps download speed and 47Mbps upload. I had similar situation with Synology RT2600ac. I wonder why I get about half of 1Gbps download speed on Lan. I wonder why is that.

Any idea?
Thanks

 

[Tech9]

Hard to tell without knowing details about how you test and with what client.

 

[snbdora]

Right. I should have provided that info. I'm using Ookla speed test cli tool on Win 11 and on Ubuntu. I did iperf3 test on a few Lan 1Gb devices I've and each one of them showed speeds >900Mbps.

 

[Tech9]

What about other speed tests?

Recently Ookla caps at around 300-400Mbps at my location, but OpenSpeedTest is showing my expected around Gigabit speeds.

 

[Tech9]

Update on Ookla:

It was my mistake, sorry. One of the QoS settings on the Gateway was left enabled after some testing and was throttling Ookla.