After playing around with different CPU, I was particular interested in the power saving technique of the CPU. It seem that the T7100 CPU could run at 3 different speed setting, 800Mhz 1.2GHz and 1.8Ghz. At each frequency the supplied voltage to the CPU is different, Using PC wizard2008 it is reported
800Mhz at 0.9V
1.2Ghz at 1.0V and
1.8Ghz at 1.175volts
The X9000 CPU however could run at many more stages
800Mhz at 0.925V
1.2G at 1V
1.6Ghz at 1.05V
2.0Ghz at 1.1V
2.4Ghz at 1.15 and
2.8Ghz at 1.2 V
From the different speed and voltage we could see the power saving between Penryn and Menrom. The newer process run at a lower voltage at 2Ghz that the Menron at 1.8Ghz.
On testing with my laptop under almost identical condition the penryn 2.8 processor could last 15 min longer that the T7100 with modest to light load. Surfing net with wireless on. And at the same time remain cooler. From my calculation the penryn CPU alone is consuming 1.48W less than the menron at this usage setting.
If I limit the CPU speed to both 1.2G using “Vista maximum processor state” the X9000 run at 44C while the T7100 run at 54C running wPrime
At 800Mhz the X9000 runs at 34C while the T7100 runs at 48C
Under heavy load the max temp the T7100 would go is 62C at1.8G. While the X9000 would reach 70C at 2.8G
at a more sane 2.4G the X9000 would match the same temperature of T7100 at 62C. This could be the fact that the heat sink and heat pipe of the SONY SZ laptop is relatively small.
This could be why the newer SZ laptop does not have a processor running at a much higher speed. The team at SONY might have design this laptop to run at max 65C or so Temp.
Assuming Temp coefficient of the Heat Pipe is identical with fan full on. we could conclude that the 2.4 G penryn consume the same amount of power as a 1.8G menron at burn speed.
It is difficult to compare the heat dissipation at the lower speed as the fan speed is not constant. so the temp coefficient of the heat pipe/fan combo is different.