Question Mysterious internet speed comparison between two computers

[whalefish]

I'm completely stumped by this. I have two computers, one a laptop, one desktop. Both running Windows 10, compared using the same identical USB 3.0 wifi adapter. The older laptop is consistently getting speeds in the range of 550mbps down, where as the very new and powerful desktop is getting speeds around 300 down. Upload speeds and latency are also worse with the desktop. I tested both in the same position in the house to account for signal loss. I've used Fast.com and Speedtest.net, and am getting the same results.

I've reset the router to factory defaults, used the same IP address to make sure it wasn't some kind of throttling from the router. I've tested the Wifi adapter on various USB ports in case there was something wrong with the hardware, and its always the same.

What on earth is causing this ~200Mbps loss between computers?

 

[kanewolf]

I'm completely stumped by this. I have two computers, one a laptop, one desktop. Both running Windows 10, compared using the same identical USB 3.0 wifi adapter. The older laptop is consistently getting speeds in the range of 550mbps down, where as the very new and powerful desktop is getting speeds around 300 down. Upload speeds and latency are also worse with the desktop. I tested both in the same position in the house to account for signal loss. I've used Fast.com and Speedtest.net, and am getting the same results.

I've reset the router to factory defaults, used the same IP address to make sure it wasn't some kind of throttling from the router. I've tested the Wifi adapter on various USB ports in case there was something wrong with the hardware, and its always the same.

What on earth is causing this ~200Mbps loss between computers?

Most likely is that the case for the desktop blocks some of the signal. If you HAVE to use USB WIFI I recommend one like this -- https://www.amazon.com/Techkey-1750Mbps-1300Mbps-Antennas-Wireless/dp/B07PKMFPF7 It has large antennas and the USB base with cable that allows you to position it away from the case for maximum signal.

 

[whalefish]

Most likely is that the case for the desktop blocks some of the signal. If you HAVE to use USB WIFI I recommend one like this -- https://www.amazon.com/Techkey-1750Mbps-1300Mbps-Antennas-Wireless/dp/B07PKMFPF7 It has large antennas and the USB base with cable that allows you to position it away from the case for maximum signal.

It isn't the case, I'm using the Netgear A7000 wifi adapter which comes with a 5ft cable. I've positioned the antenna so it is in the same exact spot plugged in to the desktop or laptop. I'm thinking it must be something software related that's throttling the connection on the desktop, or something with the motherboard, but I've tried 4 different USB ports and they are all measuring the same.

I'm should add that I've measured signal strength on both and the desktop actually reads better at -32db, which is almost perfect.

 

[bill001g]

If you think it is software try a ethernet cable so maybe you can determine if it affects all network traffic or just when it is using wifi. Should reduce the number of things you need to consider

 

[Grobe]

If you think it is software try a ethernet cable so maybe you can determine if it affects all network traffic or just when it is using wifi.

Also, if testing his then remember to deactivate WiFi on that computer (it wasn't clear for me if OP tried one single WiFi adapter for both computers or if OP have two of the same type)

 

[Ralston18]

I will add the suggestions to also try:

1) Using a known working, at speed USB extension cable to move the cradle even further away and to other locations.

2) Using another longer known working USB cable to move the adapter around and about without using the cradle.

Test both the laptop and desktop.

Objective being to narrow down some potential RX or TX problem as a matter of elimination.

Also: hardware specs for desktop and laptop. What other, if any, USB devices are being used?

 

[whalefish]

If you think it is software try a ethernet cable so maybe you can determine if it affects all network traffic or just when it is using wifi. Should reduce the number of things you need to consider

Thanks everyone for your replies so far. To clarify, I'm using the same physical adapter on both computers to eliminate variables. The adapter is placed in the same exact position for both computers to eliminate signal issues, which I've confirmed by checking signal strength with a wifi scanner tool. The only variables I can think of at this point is the physical hardware on the desktop causing an issue, or software on the desktop.

Tonight I ran an ethernet cable as suggested and tested the desktop, and am getting speeds in excess of 880Mbps. So apparently this is a problem specific to Wifi. Unfortunately running a cable isn't a solution at the moment, so I need to figure out the wifi issue.

As far as basic specs for the PC's:

Laptop: Lenovo Yoga 720 (circa 2017)
Desktop: Home built AMD 5900x CPU, MSI Mortar B550 motherboard, lots of ram, built 2021
Both are sharing a Netgear A7000 USB 3.0 wifi adapter, on 5ghz band.
Router is an Asus RT-AX68U with the latest Merlin firmware

The desktop has several USB devices connected, including a bluetooth adapter and a 2.4ghz wireless mouse adapter, keyboard, joystick, VR headset.

The mystery continues! Thanks again for your assistance.

 

[whalefish]

I figured it out!! I went down a google hole about software related internet throttling and discovered that there is in fact some poorly written software out there (MSI's LAN manager as an example) that screws with your internet speeds. Anyways, I didn't actually have that installed, but I opened task manager and started scrolling through to see if I could find anything suspect. Found a process called SWUSB.exe. I disabled it, checked my speeds, and voila, I'm at full speed. Apparently it's a realtek driver of some sort, installed by either my current Netgear wifi adapter or my older TP-Link adapter. I can't fathom why/what was going on with that process to throttle half of my internet connection, but in case anyone runs into the same issue, scan your task manager processes and try disabling some trial and error.