@Andreas Wolf, Krashan:

In anycase, "performance" must be clearly defined, because power saving is a performance as well as computation speed.
I've first think that we can multiply them (1.6 * 0.7 = 1.12), that gives the global gain.
But If we think in term of energy cost only ("perf" / watts), it's Gperf / Gwatts. That's gives 1.6/1.3 ~= 1.23

[Edit] I've mabye found how he has obtained 50% : he computes the consumption relative to the "performances" (so the oposite of power saving at the same performances).

=> 1 - 0.7/1.6 ~= 0.56, a gain of 56% on the consumption relative to the performances.


Have fun with maths

[ Edited by Yomgui 10.02.2012 - 09:11 ]