Do you have an idea what causes the extra power consumption?
When chip gets hot it starts consuming more at the same frequency and voltage. Semiconductor basics.
Thank you for your attempt at contributing something useful. Please allow me to brush up
your knowledge on semiconductor basics a little:
The microscopic conductivity of a material, sigma, can be described in terms of the motion of electrons (or other charge carriers like holes):
sigma = n*e^2*tau/m'
where
n = carrier concentration
e = electron charge
tau = relaxation time (time between collisions)
m' = effective mass of the electron
In semiconductors, the carrier concentration increases with temperature, due to excitations across the band gap Eg. So n is proportional to exp(-Eg/2kT). The relaxation time tau is inversely proportional to temperature. As the exponential dependence of n dominates,
conductivity increases with temperature in semiconductors.
The conductivity of
metals however, linearly decreases with temperature. But that effect is not sufficient to explain the almost doubling of the power draw at 448MHz, compared to 282MHz - because that would imply that the chips were running twice as hot (not in Celsius, but in terms of absolute temperature K), so that would be 500+°C.
For more details, please refer to Charles Kittel,"Introduction to solid state physics", or any other book on basic solid state physics.
So, any more explanation attempts from your side?