The sluggishness I was experiencing was caused by infowars.com.
If you leave that site open in a browser tab, it turns your computer into
a content distribution node. My machine had sent 3GB of network data.
As soon as I closed that tab, the network traffic stopped and CPU lowered
40%!
I tend to have 30 tabs open at a time so it took me a while to find out who was causing the issue. I stay the hell away from infowars now.