Performance/watt metrics and idle consumption would have been a far better way to make this choice.
If you have a choice between A) something that can dissipate 65W peak for 100 units of performance, but would dissipate 4W average under your workload, and B) something that can dissipate 45W peak for 60 units of performance, but would dissipate 4.5W under your workload... I'm not sure why you'd ever pick B.
Also, even though the CPU may draw less, can still the power supply waste more, just because it is beefy? Comparing with a sports car, they have great performance, but also use more gas in ordinary traffic? Can a computer be compared with that?
Community benchmarks, from Tom's Hardware, etc.
The vendor numbers are make believe-- you can't use them for power supply sizing or for thermal path sizing. If you look at the cited TDP numbers today-- it can be misleading-- e.g. often Intel 45W TDP parts use more power at peak than AMD 65W parts.
On modern systems, almost none of the idle consumption is the processor. The power supply's idle use and motherboard functions dominate.
> Also, even though the CPU may draw less, can still the power supply waste more, just because it is beefy?
Yes, having to select a larger power supply can result in more idle consumption, though this is more of a problem on the very low end.
