what tooling are you using to connect to the internet on your arch system for clarification? are you using dhcpd, networkmanager, systemd-networkd? Can you also provide download speeds from other things such as downloading something through the terminal through wget, downloading in a web browser, etc? What network card is on your motherboard? (this info is found in lspci), realtek wired and wireless is generally worse on linux, so if you do indeed have realtek i would recommend possibly trying with any intel wireless cards if available, these tend to have the most solid linux drivers. another shout would be maybe disabling tcp offloading on your wired connection, instructions for that can be found online, this can help. there is also this note on the debian steam page that might be of use: https://wiki.debian.org/Steam#Slow_Download_Speeds
i hope some of my info helps, and i hope some of the extra info ive asked for could maybe be used to come to a stronger conclusion. when i have time i will also look through those steam logs and see if i can notice anything.
I am using networkmanegr. Download speeds from Speedtest or wget are at about 600-800Mbps.
Network cards are:
0a:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller (rev 0c)
0b:00.0 Network controller: MEDIATEK Corp. MT7925 802.11be 160MHz 2x2 PCIe Wireless Network Adapter [Filogic 360]
I will try to disable tcp offloading.
What actually helped in Arch is setting up dnsmasq exactly as in this written guide: https://gist.github.com/FikriRNurhidayat/ce18426ad94fff2140538c0adf0e06ec
Posting in case someone stumbles upon this issue.
Nothing extracted yet.
Your system information
I am on wired connection, with SpeedTest reporting ~500-600Mbps speeds consistently.
Windows laptop connected to same access point wirelessly downloads at ~430-440Mbps, while Steam on Linux downloads at ~15-20 Mbps, peaking to ~50-60Mbps, but immediately slowing down.
ISP: Quantum Fiber (Lumen)
I tried the following recommended steps to resolve: