Thread: Overclock the N900?
View Single Post
AlMehdi is offline AlMehdi
2010-04-23 , 10:23
Posts: 1,751 | Thanked: 844 times | Joined on Feb 2010 @ Sweden
#3268
Originally Posted by egoshin View Post
It is difficult to say. The total energy from battery definitely increases with higher frequency even you run with low voltage. And most of that energy dissipates on CPU.

Just to understand better that a small example. I ran a stock kernel and measured a current from battery under different frequencies. The 250MHz (playing MP3 music) takes only around 110mA but 600MHz (hard loop in shell) takes TEN times more - around 1400mA (screen is dark etc). But CPU VDD1 voltage still differs only 1.26 times (1.58 in square).

So, the biggest power consumption increase is in frequency increase.
You still may have more bigger CPU current under high frequency which heats CPU more even with decreased voltage.
But wasn't the question how this affect an undervolted OC? I can not say i understand the matematic but shouldn't you try to compare the stock output with the OCd at different VSEL setting?

The stock takes 1.350V on 600mhz and when running 950mhz you could do it on 1.200V. The stock use far less volts on lower mhz which would explain the lesser energy consumption but the OCd use even less than stock.

So does the energy increase more if i am running 950mhz/1.200V comapred with the stock kernel? As the consumption is less i do not think so but i am not an expert on the subject.