As an observation, I've been trying an incremental back up using my Mac Mini and a 3TB drive, and as usual it was crashing. I decided to sit with the Mac to see what was happening.

If you play a film on the Mac Mini at the same time the back up does not crash for the duration that it's playing.

If you can get a copy of Modern Times Forever (Stora Enso Building, Helsinki) you might get a complete back up in one sitting.

Sooloos, Roon, G series (with LPS upgrade), 800 series (with LPS upgrade), HD621, AC200, Prime and PS, DSPs old and new.

Purdeys, Moke, Leica, 'Blad. Only the best.