[Eug Wanker]

PowerBook G5 to use Liquid Cooling?

1) Is this even a big deal? Don't the TiBook and AluBook already use heatpipes with liquid?

2) The wattage for the PowerMacs in the article make absolutely no sense (unless they're just talking about the power supplies).

3) The article seems to suggest that the same chips used in G5 Power Macs are what are going to be used in PowerBooks. I doubt this is the case. Probably we'll see a die shrunk low power low GHz version (low GHz for fall 2004).

[cdhostage]

Yah - all the Powerbooks since at least the Pismo have run too hot to just use metal conduction right next to the processor.

You can distribute heat however you like once it's gotten away from the processor itself, but that first step is a doozy. The problem with heat pipes is that they have to be pipes - you can only go in one direction away from a point source. With a heatsink, the heat goes in most of the directions of a hemisphere and is thence conducted away.

<reconsiders> It would make the construction of the heatpipe interesting, but I suppose that you could make any number of "spokes" of heatpipe with the wicking ribs all terminating in a star at the center. Put that center right on the processor, and spread the arms in eight directions, to each corner and face. The entire bottom of the computer is your sink and radiator. This design needs rubber feet to ensure airflow.

Forget that! Passive evaporative cooling is for lesser laptops! Active evaporative (refrigeration) is the way to go! So what, my computer weighs fifteen pounds and the compressor takes a minute to achieve useful pressure before the OS begins starting up. I've got a G5 on my lap!

Liquid cooling will make repairs much more interestiing, I can be sure of that.

[Eug]

Heatpipe from 12" PowerBook:

[Loopydude]

My guess is the rumor is not about the conventional heat pipe, which, as stated above, is passive.

NEC is developing a piezoelectric-pump-driven water cooling system that looks pretty, well, cool. Check out this article.

http://zdnet.com.com/2100-1103_2-1022543.html

They say it'll give you two times the cooling capacity of conventional systems, and only add 5mm of thickness to the system. But, from what I can gather about the G5, double the heat dissipation ain't gonna cut it, at least not the current generation. I had a gander at those G5 heat sinks the other day, and, DAMN, they are HUGE.

[nobitacu]

Hmmmm... intresting.....

Ming

[Eug Wanker]

Originally posted by Loopydude:
My guess is the rumor is not about the conventional heat pipe, which, as stated above, is passive.

NEC is developing a piezoelectric-pump-driven water cooling system that looks pretty, well, cool. Check out this article.

http://zdnet.com.com/2100-1103_2-1022543.html

They say it'll give you two times the cooling capacity of conventional systems, and only add 5mm of thickness to the system. But, from what I can gather about the G5, double the heat dissipation ain't gonna cut it, at least not the current generation. I had a gander at those G5 heat sinks the other day, and, DAMN, they are HUGE.

OK, I gotcha. However, 2 things.

1) The G5 I'm guessing will be a late 2004 die shrunk low-voltage 1.5 - 1.6 GHz chip, which would probably come in at under 20 Watts typical, which is about the same as the current 7447 1.33 GHz. Thus, typical passive heat pipes would be fine.

2) 5 mm thicker would be unacceptable. That's 1/5th of an inch, which is quite a bit when you're trying to keep the 17" under an inch thick.

[Loopydude]

Well, the 17" PB is massive as it is. I'm not sure if ultra-lightness is what the average 17" purchaser has in mind to begin with, but yeah, 5mm in depth spread out over that kind of footprint is a lot of extra volume.

But methinks that, given all that extra area, perhaps the depth differential could be decreased by spreading the cooling system out more in the horizontal dimension, or by some other method. I mean, from what I can see, the 17" PB is a 15" PB with a big honkin' screen. Y'know, shrink the speakers a little or someting, and I'm sure one could find some extra space in there.

That does bring up an interesting question: How much more empty space is there in a 17" PB than a 15" PB?s

Also, if one could get, say, a 50% faster G5 by using a water cooling system, but it required adding some significant extra depth to the machine, would the average consumer be willing to deal with the tradeoff? Also, what would it cost?