IBM's Power 970

[tychay]

Originally posted by jefhatfield
P4 is low heat...that is why the wintel world puts the desktop version in the wintel laptops...very low heat but the desktop processors run a lithium ion battery down in two hours or so...not good

the G4, even being much slower and less capable, does run hot but does not run the battery down too fast in the tibooks

i hope the ibm 970 with its low voltage, will be better

Pardon my ignorance (I'm no notebook expert), but this logic doesn't make sense. If something drains power, it either goes into heat or it goes into work (processing) which then becomes heat. I thought power==heat (eventually).

If something needs more power, then it must necessarily put out more heat.

As for the need to report voltage for consideration in a notebook. I imagine there are a lot of components in a notebook that attenuate the voltage, and while you can underclock a CPU to use less power, it is very hard to have it so it uses less voltage. Thus the CPU voltage requirements (peak voltage requirement must be less than ~1.3V) counts against the budget of the laptop and thus becomes an issue in design. Also, power consumption scales as the square of the voltage (assuming power lost to leakage and DC current is small), so lower voltage requirements (both in the CPU and the components) mean less power needed, thus less need for power dissipation (heat issues). Of course, we already have the power reported separately from the voltage.

The conclusion is that the CPU in the G4 Ti creates less heat than the CPU in a Intel P4 notebook. Ahh! you say, that's not true because the G4 Ti is hot!. Inconsistent with observed fact, you say.

Unless there is a perpetual motion machine in Pentium notebooks, lets consider some alternatives.

1. A Pentium notebook chip is a "SpeedStep" chip which basically underclocks when it can get away with it--for instance, as soon as it is unplugged from the wall. Since power is proportional to the frequency (again assuming your DC/leak dissapation is negligable), you can get almost twice the battery by moving almost half as fast (which is what the P4SpeedStep does). Those of us who used old Powerbooks are well familiar with this "technology".
2. The Ti notebook is 1" thin, no full-featured notebook in the PC world comes close. There must be some serious convection problems in this design.
3. The Ti notebook is designed to dissapate heat through the keyboard and in the body. I don't know how good at conducting titanium is (not good, I imagine), and the keyboard isn't the best place to be dissapating heat.
4. The Ti case is the conductor, in most PC notebooks the case is a bunch of plastic that insulates the user from the heat (which probably escapes through vents on the sides and back).
5. The Ti notebook's fan doesn't kick in until the computer gets very hot.
6. Modern PC notebooks have a liquid cooling (heat pipe) system and two fans. I think the Ti has 1 fan and no heat pipe.
7. Intel created a program a few years back to look into this very thing. It advocated changes in software (to throttle the voltage between keystrokes, for instance) and lower voltage components (see voltage->power relationship above) to reduce power consumption of notebooks because they were getting outrageous (the notebooks were getting hotter at a faster rate then redesigns could dissipate the heat). Some of that must have paid off by now.
8. Maybe PC users don't bitch about their computers as much as Mac users. (It always seemed to me that many mac users expect Apple to defy the laws of physics.)

Ironically, in the PC world, heat is the major power issue, not battery life--I guess these people long since gave up the notion of being able to watch a DVD on your notebook on a nonstop flight.

Sound more reasonable?

 

[jefhatfield]

Originally posted by tychay


Pardon my ignorance (I'm no notebook expert), but this logic doesn't make sense. If something drains power, it either goes into heat or it goes into work (processing) which then becomes heat. I thought power==heat (eventually).

If something needs more power, then it must necessarily put out more heat.

As for the need to report voltage for consideration in a notebook. I imagine there are a lot of components in a notebook that attenuate the voltage, and while you can underclock a CPU to use less power, it is very hard to have it so it uses less voltage. Thus the CPU voltage requirements (peak voltage requirement must be less than ~1.3V) counts against the budget of the laptop and thus becomes an issue in design. Also, power consumption scales as the square of the voltage (assuming power lost to leakage and DC current is small), so lower voltage requirements (both in the CPU and the components) mean less power needed, thus less need for power dissipation (heat issues). Of course, we already have the power reported separately from the voltage.

The conclusion is that the CPU in the G4 Ti creates less heat than the CPU in a Intel P4 notebook. Ahh! you say, that's not true because the G4 Ti is hot!. Inconsistent with observed fact, you say.

Unless there is a perpetual motion machine in Pentium notebooks, lets consider some alternatives.

1. A Pentium notebook chip is a "SpeedStep" chip which basically underclocks when it can get away with it--for instance, as soon as it is unplugged from the wall. Since power is proportional to the frequency (again assuming your DC/leak dissapation is negligable), you can get almost twice the battery by moving almost half as fast (which is what the P4SpeedStep does). Those of us who used old Powerbooks are well familiar with this "technology".
2. The Ti notebook is 1" thin, no full-featured notebook in the PC world comes close. There must be some serious convection problems in this design.
3. The Ti notebook is designed to dissapate heat through the keyboard and in the body. I don't know how good at conducting titanium is (not good, I imagine), and the keyboard isn't the best place to be dissapating heat.
4. The Ti case is the conductor, in most PC notebooks the case is a bunch of plastic that insulates the user from the heat (which probably escapes through vents on the sides and back).
5. The Ti notebook's fan doesn't kick in until the computer gets very hot.
6. Modern PC notebooks have a liquid cooling (heat pipe) system and two fans. I think the Ti has 1 fan and no heat pipe.
7. Intel created a program a few years back to look into this very thing. It advocated changes in software (to throttle the voltage between keystrokes, for instance) and lower voltage components (see voltage->power relationship above) to reduce power consumption of notebooks because they were getting outrageous (the notebooks were getting hotter at a faster rate then redesigns could dissipate the heat). Some of that must have paid off by now.
8. Maybe PC users don't bitch about their computers as much as Mac users. (It always seemed to me that many mac users expect Apple to defy the laws of physics.)

Ironically, in the PC world, heat is the major power issue, not battery life--I guess these people long since gave up the notion of being able to watch a DVD on your notebook on a nonstop flight.

Sound more reasonable?

i am an engineer in IT so i will try to explain this in the simplest terms

in the manufacturing of processors, there is this concept of using increasingly smaller micron technology to put more transistors in a processor and use less voltage but at the same time have a better clock rate

as it turns out, throughout the industry, processors have generally become more efficient with less voltage until we have the situation we have today with the pentium 4 which could be used in a notebook without draining a battery too fast

at the same time, batteries in notebooks have gone from ni-cad to nimh to liion, with the latter giving the most time

so today, a pentium 4 desktop processor with a relatively good liion battery in a notebook will give the user a swift computing experience and still get good battery life

intel does make a pentium 4 mobile processor which utilizes the battery more efficiently

i hope this helps and pardon me if you know some or all of this stuff concerning laptops/notebooks

 

[Telomar]

Originally posted by jefhatfield


P4 is low heat...that is why the wintel world puts the desktop version in the wintel laptops...very low heat but the desktop processors run a lithium ion battery down in two hours or so...not good

but there is no overheating with the desktop P4s in the PC laptops

the G4, even being much slower and less capable, does run hot but does not run the battery down too fast in the tibooks

much of the heat goes into the titanium case which makes the user get burned on the legs but at lest that heat is not in the system which would slow it down

Actually the PIV is a rather hot processor compared to the PPC chips. The only reason it has found its way into laptops is because firstly it is cheaper than the mobile version and secondly it has very good thermal management (ie. it lowers it clockspeed as it gets too hot). Just take the heatsink off a PIV and you will see what I mean, although I wouldn't advise leaving it off too long.

You need only look around Intel's website to find their concern with regards to the upward trend of processor heats.

When computer manufacturers first started the practice of packaging desktop CPUs into mobile computers Intel issued a warning regarding possible failures from heat and that their warranty didn't cover it. Most places therefore use a PIV-M, which is a PIV modified for Mobile usage.

The PIV itself generates 68.4W at 2.8 GHz (PIV-M @ 2.2 GHz is ~30/20W). That compares to the G4, which is around 26W @ 1 GHz on an older manufacturing process and 42W @ 1.8 GHz for the PPC970 or 19W for the 1.2 GHz version.

If ever you buy a heatsink it will have a rating in K/W that tells you the temperature rise that will occur given a certain power production of a processor. Generally you will find the PC world uses much better quality heatsinks.

The reason the TiBook has heat problems is because the case itself is part of the heatsink (a particularly poor design) to enable that sort of form factor to be obtained.

 

[jefhatfield]

Originally posted by Telomar
Actually the PIV is a rather hot processor compared to the PPC chips. The only reason it has found its way into laptops is because firstly it is cheaper than the mobile version and secondly it has very good thermal management (ie. it lowers it clockspeed as it gets too hot). Just take the heatsink off a PIV and you will see what I mean, although I wouldn't advise leaving it off too long.

You need only look around Intel's website to find their concern with regards to the upward trend of processor heats.

When computer manufacturers first started the practice of packaging desktop CPUs into mobile computers Intel issued a warning regarding possible failures from heat and that their warranty didn't cover it. Most places therefore use a PIV-M, which is a PIV modified for Mobile usage.

The PIV itself generates 68.4W at 2.8 GHz (PIV-M @ 2.2 GHz is ~30/20W). That compares to the G4, which is around 26W @ 1 GHz on an older manufacturing process and 42W @ 1.8 GHz for the PPC970 or 19W for the 1.2 GHz version.

If ever you buy a heatsink it will have a rating in K/W that tells you the temperature rise that will occur given a certain power production of a processor. Generally you will find the PC world uses much better quality heatsinks.

The reason the TiBook has heat problems is because the case itself is part of the heatsink (a particularly poor design) to enable that sort of form factor to be obtained.

p4 may not be as cool as an ice cream pop, but have you tried a pentium 4 desktop chip driven laptop...it's really not that hot

now try my old '98 era k6-2 running laptop built on .25 micron technology...now that is hot and it slows down after one hour of use when it heats up...i don't notice that on pentium 4 laptops at all

of course, it may benefit from a better cooling system like the k6-2+ which followed it and was much cooler and nearly 200 mhz faster...i believe that chip employed .18 micron chip fabrication process

and we are still talking old stuff, since neither chip is found in today's laptops which on the low end, will sport an amd duron at twice the speed of the k6-2+

unless, of course, if you want to go that other way and spring for a celeron running laptop on the lower end