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PowerMac G5 Picture Gallery
NivenHuH writes "Bill Noll, an independent photographer, took some interesting pictures of his new PowerMac G5. Talk about Mac Zealot!"
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The fans in the G5 are computer controlled. They are only on when they are needed.
According the Jobs (paraphrased): "You might think '9 fans? Oh my god' But it turns out the opposite is true. We've gotten the noise down to 35dba at room temperature, 3x quieter than the latest G4".
Vonal Declosion
The fans are variable speed and spin up faster as the machine gets hotter... I was looking at a demo 1.6ghz unit in the store (at a micro center in one of their tech rooms) and it was pretty silent...
Just when you make it idiotproof, some idiot builds a better idiot.
1) I went to the local Apple Store over the weekend. The 1.8GHz machine was there, and I couldn't hear the fans, even with my head next to the machine.
2) I dunno.
3) Only the dual 2GHz machine has 9 - there are fewer in the single proc models. They have implemented a cooling zone design in the case - different zones have different cooling requirements. It's a really neat idea. The fans are large and rotate slowly, and thus produce virtually no noise. When the case is closed, you DON'T hear them. The aluminum case is unlike aluminum PC cases - the aluminum is very thick. Nice.
The fans are computer controlled.
Go check a system out at your local Apple Store(tm).
Wish I had the money for one, but I gotta get a new car first. *sigh*
I found the spoof far more interesting/amusing than the main page..oh well, something for everyone i suppose.
I'm not going to be 100% convinced it works until the machines have been in use for a while, but I know the principle Apple's had to work with is that the G5 is a heat radiating monster. A single fan would have to run quickly and suck a single stream of air through a preset path to cool the PowerMac G5. It would, frankly, sound like a plane taking off. So Apple has dotted fans around more to guarantee that airflow, and hence cooling, will happen over each part of the machine. Because there are more fans, and because the airflow is more targetted, the fans can run slowly, and the noise control is better.
My PowerBook, which uses a nice, cool, 800MHz G4, sounds like Miami Airport whenever I play a FPS game. I'm glad Apple are experimenting with cooling systems rather than just following the herd.
You are not alone. This is not normal. None of this is normal.
Sony DSC-F717. More info Here
The 35 dBA spec is basically useless since it's given without a reference distance. With that in mind, 35 dBA is roughly the sound of a soft whisper at 5 feet (Ref: Martin Hirshorn, Noise Control Handbook). That's pretty darn quiet, assuming it refers to a reasonable distance from the chassis, say 3 to 5 feet.
My Panaflos are rated at 22dba, and I certainly wouldn't call them "silent".Than they're probably louder than 22 dbA. 22 dBA is roughly the sound level at a remote area, at night, with no insect sounds or wind. If you live in a very quiet area, the sound level in your room may approach 25 dBA if your walls are well insulated, and no windows are open. No consumer sound level meter (Radio Shack brand, etc) would be able to accurately measure that low, and many professional level SLM's would have difficultly measuring that low (for example my $1800 TerraSonde ATB Pro has a noise floor of about 25 dB with its stock microphone).
Of course this all completely ignores the fact that measuring the sound level of a sound source that is lower than 40 dBA is pretty hard to do outside of an anechoic chamber since ambient sound levels can contaminate the measurements...
The key to Apple's design is to:
- lower the RPM of each fan,
- lower the air flow velocity,
- lower the total CFM required by all fans, and
- reduce the turbulence of the airflow.
A single fan design has the disadvantage of having to move enough air to cover the worst case configuration of internal components and thermal loading -- ensuring that some air gets to every nook and cranny. With 9 fans in 4 thermal zones, each zone of the G5 is regulated to minimize fan speed whilst maintaining acceptable temperatures. More fans for more fan cross-sectional area also reduces noise. A single fan design requires higher velocities on the blades and airflow and creates more turbulent airflow. Thus, for example, blowing 24 CFM though a single 120 mm fan makes more noise that blowing the same 24 CFM through an array of three 90 mm fans.
The front and back mesh covers act as a acoustic diffusers and help create laminar flow (which is less noisy than turbulent flow). Finally, the flow-through design creates a uniform convective flow over the components versus other designs with more convoluted airflows that create uneven flow or dead-air zones in the case.
Two wrongs don't make a right, but three lefts do.
Damn,
Not Safe For Work.
NSFW.
I really hate Dan Patrick.
I echo Tumbleweed's experience. I saw the 1.6 Ghz at an Apple Store in Dallas. There were very few customers in the store and I would not say it was any louder in there than in my house with someone else home. Unless I put my ear up to the heavy plastic (think the clear plastic used on the Apple Pro Mouse or the edges of the 17" iMac screen) I could not hear any of the 3 fans I saw spinning.
I think the key is the low RPMs. with it spinning slower, there isn't a "whirrr" sound. Since the sound is not as high pitched, the sound is deadened sooner by the materials in the case.
And Apple a day keeps Gates at bay
I only came here to do two things; kick some ass, and drink some beer...looks like we're almost out of beer.
They run at very low speeds and are all monitored by the computer.
The old g4 towers used one large sideways mounted fan to blow air over the passive heatsink of the CPU(s) and other components, and the system would even run when the side was open (the motherboard was attached to the side that opened so that it was flat on your desk to facilitate easy upgrades).
The G5's 'zones' are well thought out. Only the dual G5 has 9 fans. The single processor 1.6 and 1.8Ghz only have 7 fans.
Each processor's heat sink is located in the centre of a "wind tunnel" (which is formed by two bulkheads, the motherboard and the clear perspex panel). The frontmost bulkhead has a low speed fan and the heatsink with its 40 metal fins, which are aligned parallel with the airflow, is set back about 10cm (5") from this fan. A further 4 or 5" behind the heatsink is another fan that is rarely switched on. The combination of these two fans and the design of the "wind tunnel" keep each cpu cool enough without having to run the fans at high speed.
I've examined the inside of a 1.6Ghz G5 quite closely (I have a friend at my local Apple store) and I'm impressed by the design - it was obviously very carefully thought out and was only possible because they could design every thing to fit - when you design the motherboard and the case you can ensure that you get the best fit.
The computer is always monitoring and will spin up the rear fan to a low speed when the cpu is working hard to create lower pressure behind the heatsink which promotes airflow over it from the front without having to speed up the front fan. We worked it quite hard and I never saw the front cpu fan spin up any faster or make any more noise than a quiet "swoosh" the whole time, and we were running it with the metal panel removed (but the perspex cover still in place).
An interesting note though - if you remove that perspex cover while the computer is on it automatically spins the cpu fans up to full speed to ensure the cpu doesn't overheat because the wind tunnel has had a side removed, thus reducing the airflow over the heat sink. We called it a "headless chicken panic" since the noise from the fans is very noticable compared to normal running when you almost can't hear them at all and we likened it to the computer getting all confused with its side removed and running round the yard in a daze.