P8400 vs P8600 CPU

After I order my t400 I started wondering about something. I went with the p8400 for battery life, and because the extra 140mhz was not worth the 50$.

But then I realized that they both have 25W power consumption at Maximum load

so that means that its 25w at 2.4ghz on the p8600, and 25w at 2.23ghz on the p8400, would this scale down exponentially?

I dont know exactly how do speedstep on these works, but I think they are both at 800mhz idle.

Does this make any sense? I know these are not real world numbers, but it gives a good scale to compare

 

25watts is the TDP (Thermal Design Power) required to cool the cpu. Do a quick google for more info

Its not electrical consumption.

 

Power consumption depends on the speed and voltage
The equation is something like this
P=C*F*V^2 C=capacitance F=frequency V=voltage.
Intel's 25 watt rating is only a estimation.

 

You should try undervolting to reduce energy usage.

 

Ya and various batches with various steppings can cause CPUs to behave differently (no CPU is the same). But that isn't as relevant in a laptop, but it could affect undervolting.

 

oh. I didnt realize it was thermal design power, but that still doesnt rule my idea out..

I know what it depends on, does anybody know the voltages for the p8400/8600?

And I haven't even gotten my laptop yet, so I cant really under volt... I read somewhere that it is impossible to undervolt core 2 duo's at idle anyways.

 

According to Notebookcheck.net, the P8400 and P8600 use about the same amount of power: http://www.notebookcheck.net/Comparison-of-Intel-Centrino-2-CPUs.11100.0.html (scroll to bottom for power consumption comparison).

 

rep+
Thanks, it seems like the p8400 has a lower power consumption at idle, and the p8600 is lower at load.

 

It is likely that both cpus are produced at the same production line. Depending on how far Intel has proceeded with the manufacturing quality, the difference between the two cpus might be very small.

In regards to the notebookcheck numbers, you are likely to get other values between two other P8400 and P8600 cpus, due to the individual variations between cpus.

 

not much of a difference, but if you are concerned about battery life?...get a 9-cell and ultrabay battery....then come back with your notebook set at maximum performance and report your run-time.....Vola

 

Yes... I need at least 7 hour to get throu a day of school, and since I live in the Czech Republic but study in FL I fly back and forth a lot, about 13-14 hour flight time... very enoying without a laptop

and I am getting the 9 cell+ ultrabay....

I will report back detailed battery tests once I get it, it was supposed to ship today(sunday???? ) I just hope there is not another delay