Was dealing with a weird issue at work today on 3 Asus G751 laptops we have - slow TCP download speeds to far away servers (high RTT). Download speed to close servers was mostly fine.
Ended up finding the article here that helped me figure out what the issue was:
https://www.duckware.com/blog/how-windows-is-killing-internet-download-speeds/index.html.I bet if you run
netsh interface tcp show global on your machines you may find that
Receive Window Auto-Tuning Level is disabled. The issue with this is that it keeps the flow window too small for far servers to provide you with the download throughput you might be capable of handling.
For our machines I enabled the auto-tuning with
netsh interface tcp set global autotuninglevel=normal and this made a drastic difference for our download speeds to servers on the east coast (we are on the west coast).
If you want to run a test to confirm this, I recommend picking an s3 bucket for a test
here that is a bit farther away from you and comparing the results you get with the auto-tuning set to normal and with it disabled.
