An interesting point is I can imagine that the actual power savings from upgrading those machines are non-trivial at this point. Most of the machines that would

An interesting point is I can imagine that the actual power savings from upgrading those machines are non-trivial at this point. Most of the machines that wouldn't be able to run anything past XP are probably Pentium 4's--which are going to use 2-5x the power at idle of anything vaguely modern. Can you not move your machine's software installations to a VM, and continue to use those old apps on there?