“TCP Receive Window”? “Path MTU Discovery”? “Black Hole
Detection”? If those terms mean anything to you, you can grab Dr.
TCP to tweak those settings on your legacy Windows PC (XP and
earlier). You can find instructions on how to do so in the old, but
solid, PCWorld article Unclog
Your Net Access for Fast Relief.
Note: This link takes you to the vendor’s site,
where you can download the latest version of the software.