[Ti] Macbook pro version 2...

[Kynan Shook]

Your "master CPU chart"???  Did this come with your crystal ball and  
magic wand, or did you have to buy it separately?

I guarantee you that a G4's maximum core temperature is nowhere near  
44°C.  For starters, most commercial grade electrical components have  
a specified operating range of 0 to 70 degrees C.  Unless you've  
managed to engineer something rather unusual, you're not going to get  
a 44°C junction temperature in 70°C ambient.

Next, the maximum junction temperature for both the G4 (including the  
7447A) from Freescale as well as the G5 (including the 970FX) is 105° 
C.  The maximum junction temperature for the Intel Core Duo is 100°C;  
a negligible difference.  Now, this has a lot of room for local hot  
spots, a safety margin, measurement error, etc; after all, the G4's  
storage temperature range goes up to 150°C; this is a typical maximum  
limit for semiconductors.  Most have a specification of 125°C max to  
give them some margin; since CPUs consume so much power and are  
typically made with the smallest, most advanced process available,  
they get even more of a margin.

As far as power consumption goes, the following values are direct  
from manufacturer datasheets of the maximum power draw at the highest  
speed listed: G4 at 1.42 GHz: 30 Watts.  Single-core G5 at 2.2 GHz:  
76 Watts.  Intel core duo at 2.16 GHz: 31 Watts.  It's not quite as  
low as the G4, but it's close...  AND it has two cores.  For that  
matter, the G5 listed above running at half frequency (1.1 GHz) in  
Nap mode (the lowest of the low-power modes) at normal voltage still  
sucks down 37 Watts at its maximum.

As far as various temperature measurements go, I won't profess  
knowledge; I no longer work for an Apple Authorized Service Provider,  
so I can't tell you with any certainty what is or is not going on in  
the world of manufacturing them.  However, I can tell you that it is  
almost certain that they are using better temperature sensors than  
they have previously.  And by better, I mean more about improved  
location than anything else.  The temperature gradient in a computer  
can change by 100 degrees in just millimeters, depending on how it is  
designed.  If you put your temperature sensor in the wrong spot, it  
doesn't do much good.  Typically what a designer will do is place the  
temperature sensor in as good a location as possible, then do testing  
with a thermocouple or other device while testing alpha versions of  
the hardware.  You might find that the location of the temperature  
sensor is 40° cooler than the junction temperature, then throw in an  
extra 7° safety margin: presto, you'd get a G5 that won't go above 58° 
C without the cooling system kicking into high gear.


I am continually amazed that you can flap your mouth about such  
things, Chris.  I really wish you'd give it a rest - I have a lot to  
do this week!  ;-)


Chris Olson <chris.olson at astcomm.net> writes:
> On May 8, 2006, at 12:04 AM, Alan Vonderhaar wrote:
>> Nonsense. My core duo runs cooler than either my 15" Ti or 17" Al.
>
> You might *think* it runs cool if the thermal conductivity system
> (heat pipes and sink) is working correctly.  Referring to my master
> cpu chart, the Core Duo runs at a core temp of 90°C, or 1.54x that of
> a dual core PowerPC G5 who's max core temp is 58°C, and 2.04x that of
> a G4/7447A who's max core temp is 44°C.
>
> "Power per watt" really means the ability to fry more eggs and bacon
> on the same power consumption.
>
> The GPU in the PowerBook runs approx 2x as hot as the G4 CPU.