Faster rsync?

[Adam Kessel]

I've found rsync to be painfully slow on large folders -- hours to sync 
thousands of files, even when they already match size and --size-only is 
used. It's much faster between native Linux boxes. Is there any trick to 
improving performance? I've been looking for a native version for 
Windows, but it doesn't appear to exist -- as best I can tell, 
https://acrosync.com/windows.html is just the cygwin version packaged up.

 From past experience, WSL rsync is much faster, but I don't want to 
install WSL on this box.

Any ideas?