I'm running Ubuntu 22.04 and Windows 7 on a laptop and the wireless performance is about 7-10x better on Windows, measuring using an internet speed test. There's no problem with the internet connection, since I measure it directly over wire using a Raspberry Pi. The WiFi access point (router) is 2.4 GHz 802.11n only.
Wired, Laptop and Raspberry Pi
- 95 Mbit/s consistently, up and down
Wireless, Laptop, Ubuntu (typical)
- Download: 3,272 Mbit/s
- Upload: 1,024 Mbit/s
Sometimes, spuriously, it can reach around 13 Mbit/s.
Wireless, Laptop, Windows
- Download: ~26 to 42 Mbit/s
- Upload: ~29 to 35 Mbit/s
It doesn't matter if the laptop is right next to the access point or a few meters away -- same result in both OSes.
Conclusion:
It's not the internet connection -- it's stable. It's not the access point -- other devices perform well with it (iPhone 8, Macbook Air) and the same device also performs well in Windows 7. Then it must be Ubuntu in combination with this Wifi card.
I followed a suggestion in another question about how to determine a good MTU, but couldn't conclude anything other than the currently used 1500 was correct.
Is there a way to fix this or is Ubuntu simply not suitable for this machine?
*-network
description: Wireless interface
product: AR9485 Wireless Network Adapter
vendor: Qualcomm Atheros
physical id: 0
bus info: pci@0000:02:00.0
logical name: wlp2s0
version: 01
serial: 94:db:c9:af:a1:7d
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless
configuration: broadcast=yes driver=ath9k driverversion=5.15.0-27-generic firmware=N/A ip=172.20.10.3 latency=0 link=yes multicast=yes wireless=IEEE 802.11
resources: irq:17 memory:f7d00000-f7d7ffff memory:f7d80000-f7d8ffff