Screw the server load (for now) :p
PC slowed right down so I had a look in Task Manager - Memory usage had peaked (has pretty much never done that before).
TM said the culprit was Chrome - so I looked in the Chrome TM, which said the culprit was TDU-Central (only had 4 or 5 tabs open).
Terminated those 4 tabs and the memory usage dropped immediately and the PC was responsive again.
Last thing I did was edit one of my posts.