I recently made the jump to upgrade to Windows 11 (first on my 4-year-old HP Spectre Laptop, then on my Ryzen Zen 3 Desktop).

Almost immediately, I noticed that my download speeds were a fraction of what they used to be (1/20th).

Turns out this is an issue with auto-negotiation on my onboard Realtek NIC.

This is easily fixed by specifying the highest supported setting on your network. For me, 1 GB.

See screenshots!

NOTE: The before image is broken because OVH sucks and deleted both my server and backups without giving me the 60 days warning they said they would and only contacted via email….

After (switching back – you can see the speed drop dramatically):

Changing the setting (under Device Manager => Network Adapters => (In my case, “Realtek PCIe 2.5gbE Family Controller”) => Properties => Advanced => “Speed & Duplex”

I hope this helps someone else out there!

NOTE: After toggling this setting (reverting the change) it still seems to work…. Argh.. $MS.