i have a acer aspire with a i5 430m which has a tdp of 25watts. in the sensors i see that i get reports of power usage from 6 to 25 whr. how accurate is this measurement? is it an aproximation? i see that my i7 860 (destop) has no such info.
I'm not sure which particular sensor you mean, but I assume it's the "Intel PCH" one.
So in this case - No, this is not an estimation (like some other tools use to report based on TDP and current P-State). It's a real measurement using a CPU energy counter. According to Intel this should be precise. Theoretically there might be just a small difference due to time-delta delay.
AFAIK, no other tool is able to report this kind of information so far. Not all platforms support this reading - it needs to be supported by platform/BIOS.