PPC970FX Power dissipation

E

ericmurphy

Registered
I was reading that the PPC970FX (the chip that ships in the new PowerMac G5s and the Xserve) dissipates 24.5 watts at 2.0 GHz. If this is true, then why is getting a G5 into a laptop such an engineering challenge? The hottest P4 chips used in laptops ran about 30 watts (and the next-generation desktop P4s dissipate 130 watts!), so while it might be unrealistic to run two 970FXes in a laptop, one seems pretty feasible.

Are my figures wrong, or am I just stupid?
 
I'm sure it's perfectly feasible to get a G5 into a laptop immediately, but you'd have a much larger case than current PowerBooks have, and it would be a hot-box that sucks battery power in an hour. Have you used those P4 laptops? They get hotter than any PowerBook I've used.

I'd be willing to be that it's not just the engineering hurdles that Apple is trying to overcome, but also the design of the G5 PowerBook that's taking so long. The numbers say "yes," and that's why it will happen -- but building the damn thing is probably what takes so long.
 
After I posted this, I was wondering about that myself. If Apple wanted to put out a 2-inch thick brick of a laptop with a G5 in it, they could probably do it tomorrow. But an "unreasonably thin" G5 laptop will probably take a while. 2Q 2005, maybe?
 
I'm thinking the end of 2Q 2005, possibly. I doubt we'll see it for the majority of this year -- I'm putting my money on December 2005 or 1Q 2006.

By that time, I think IBM could work out most of the kinks in their 90nm process, which would yield smaller chips more suitable for laptops.
 
Heat and battery life aren't the problems keeping the G5 out of the Apple notebook lines. It's supply. IBM is still having supply issues with the G5 chips.

In theory, the G5 should actually be cooler than the current G4 chips running in the books (at the same speed). The G4 at 1.4GHz is 21w, where the G5 only consumes 13.2w at 1.4GHz. There's other factors, but the energy draw is a large one where heat is concerned.
 
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