Bump, and: I am now also getting lag spikes of a similar duration during other games, even if Crossfire Mode is off. I think this happened after I set the GPU settings to High Quality in Windows, so I am going to go look and see if I can change it back to fix it. I used not to have lag spikes in some games that I now have lag spikes on on the same computer, and it's not a network thing. I also updated the R7 driver through Windows just now--from May 2017 to October 2017 version (most recent version), so we'll see if that fixes it. One thing at a time, though. I'll keep results posted.