Power consumption of the Realtek 8192CU based USB wireless adapter

Under Linux, the Realtek 8192CU based USB wireless adapter has a beacon based management for power savings. When it is set to maximum (kernel module parameter rtw_power_mgnt), the adapter answers only every third beacon packet of the wireless router. I have the following observations with my router:

- Setting the beacon interval of the router: it does not effect the power consumption of the wireless adapter.
- Setting the power management to minimum (rtw_power_mgnt=1): the adapter consumes: 0.5-1.0 W in idle.
- Setting the power management to maximum (rtw_power_mgnt=2): the adapter consumes: 1.0-1.5 W in idle.

Verdict: it is the best to use the power management to set to minimum. The maximum "power saving" consumes more energy (by 0.5 W) significantly.