Internet speed is now slow on my Mac, but fast on my PC

[barnstorm]

Internet speed is now very slow on my Mac Mini (mid 2010), but normal speed on my PC.

This just started happening. I don't think I changed anything recently. Maybe a recent update to Sierra 10.12.6. and a recent boot up problem.

Same thing whether I have the Mac or PC hooked up with ethernet or wireless. Same cables, etc.

 

[Boyd01]

FWIW, I'm running 10.12.6 on a 2012 Mini and 2013 MacBook Air with no problems. Do you have a clone of an older operating system that you can boot into for testing?