Re: Maybe this will encourage popularizing low wattage cpu's
Sadly, you've missed the forest for the CPU tree. :)
Firstly, the wattage ratings are intended as indications of the *maximum* power used under constant full load, just as the CPU internal clock is a ceiling, not a constant. Modern CPUs, dynamically adjust their clock speed, internal voltage, etc to provide just enough performance to accomplish the requested tasks, wasting little energy on full voltage or clock when the load is low. Thus, your 2GHz low-performance CPU is severely limited in its maximum performance vs. a standard 3.5GHz Intel CPU like the i5-6500 (65W maximum TDP), but likely uses not much less power when both are at idle.
Secondly, the relevant power use is the system's power use, not just the CPU. Depending on the chipset, motherboard design, memory type, power supply, and other components, as likely as not your AMD system uses more power on a system basis when idle than does an equivalent system built around the i5-6500.