A white paper released by Mindteck, an IT services and consultancy company, contains data about Windows PC power consumption during idle, low-use and high-use scenarios.

The paper, titled Enabling Green Computing with Windows 7, is primarily  concerned with the benefits of implementing power management policy on Windows 7 computers. However, of probably more interest to our clients, they also investigated the difference between Windows 7 and Windows XP.

	Power consumption (Watts)
OS	Windows XP			Windows 7			Percent improvement
PC Configuration	Idle	Low	High	Idle	Low	High	Idle	Low	High
Older Desktop (P4)	64.2	68.7	106.2	57.3	66.1	79.4	10.75%	3.78%	25.24%
High-end Desktop (Core i7)	50.5	54.3	78.0	45.2	49.1	66.8	10.50%	9.54%	14.36%

 

Windows 7 performs better even with older hardware (Dell Pentium 4 Desktop). These results are for the standard out-of-the-box drivers, but Windows 7 still performs better in every scenario with manually updated drivers for the specific chipset.