# Heat issues with new Powerbooks?

Posted:
edited January 2014
According to the specs of the Freescale 7447B the 1,67GHz runs on a higher voltage than the 1,5GHz. 1,28v vs 1,2v.

Instead of power output scaling with clock-speed, the 1,67 now draws ~25% more power than the 1,5. I'm thinking this should result in a hotter computer and more fan activity.

Anyone receiving both models and can do a comparison?

Quote:

Originally posted by palled

According to the specs of the Freescale 7447B the 1,67GHz runs on a higher voltage than the 1,5GHz. 1,28v vs 1,2v.

Instead of power output scaling with clock-speed, the 1,67 now draws ~25% more power than the 1,5.

I'm not an engineer but simple math tells me that 1.28V is 6.7% higher than 1.20V. I don't know how you got the 25% increase. Is there some complicated math involved?
Quote:

Originally posted by BeigeUser

I'm not an engineer but simple math tells me that 1.28V is 6.7% higher than 1.20V. I don't know how you got the 25% increase. Is there some complicated math involved?

Not that complicated. To calculate power draw voltage is squared and MHz is linear. So to get the relative numbers I did the following:

1,67*1,28^2 = 2,736

1,5*1,2^2 = 2,16