I suspect there is a tipping point, but that it's probably much lower than you suggest: maybe 10-25% of a single core, thus some single digit percentage of the

I suspect there is a tipping point, but that it's probably much lower than you suggest: maybe 10-25% of a single core, thus some single digit percentage of the entire processor. Modern Intel processors can shut down unneeded cores almost completely, and frequency scaling gives you another range of efficient power reduction. It's only when you get lower than that that you are losing significant power at 'idle'. Unlike a small battery powered device, I'd guess that the difference in idle power for the CPU is never going to be the deciding factor, as keeping the non-CPU rest-of-the-machine running will dwarf the difference. What workload would you envision as having the greatest advantage? Maybe if you were running a single instance per dedicated core?