Powermac G5 fans

The three bladed fan is for in front of the CPU, the multi-bladed fan is for after the heatsink.

They are different because they need to move the same amount of air, but have different space allotments and they both must be as quite as possible.

Intell said:

They are different because they need to move the same amount of air, but have different space allotments and they both must be as quite as possible.

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I never cared much for quiet fans... quiet fans mean weak airflow. Atleast with a PowerMac or PC fan on full bore i know they are getting the maximum amount of airflow possible. If it wasn't for the MDD's main fan sounding like a jet engine id run it at full bore unfortunately i have done that before and it was so loud i couldn't watch TV or even play iTunes of it as even the sound on max was drowned out by the fan

It's about the same, not better not worse.

poiihy said:

Some fans have 3 large blades, while other fans have more smaller blades which looks like a typical fan. Why is that? Is it any better? How does it compare to typical fans in noise, airflow, power consumption, efficiency, etc?

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It looks like the 3 blade fans could be replaced by regular and quieter PC fans (with modification of the fans) assuming you can get a PC fan in the same size.

That would not be recommended. Those fans are specially designed for the G5. Using different fans would inhibit the cooling abilities of the system.

MatthewLTL said:

It looks like the 3 blade fans could be replaced by regular and quieter PC fans (with modification of the fans) assuming you can get a PC fan in the same size.

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Have you ever used a G5?

I have the front of one sitting about a foot and a half from my left ear as I type this.

The fans just aren't that loud in normal use. Granted I'm working in a lab with a lot of background noise due to ventilation(our HVAC system does a complete air change in the room roughly every 3 minutes) but I don't hear them unless I'm listening for them. The only time they get loud is if you're really crunching on it hard and heating up the processors, or if you spend a lot of time in Open Firmware, Apple Hardware Test, or some mode like that where the computer doesn't control the fans and just runs them at full blast.

MatthewLTL said:

I never cared much for quiet fans...

...unfortunately i have done that before and it was so loud i couldn't watch TV or even play iTunes of it as even the sound on max was drowned out by the fan

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So why would that be a problem since you think so little of quiet fans?
I have no time for noisy fans - I prefer efficient. Noisy fans are not necessarily better, just more attention seeking.

http://www.quietpc.com/casefans

weckart said:

So why would that be a problem since you think so little of quiet fans?
I have no time for noisy fans - I prefer efficient. Noisy fans are not necessarily better, just more attention seeking.

http://www.quietpc.com/casefans

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On a totally different scale, find an desk fan from the 1950s or earlier and compare it to a similarly sized fan made in the past few years.

Chances are, both will move a similar amount of air, but the new one will make a terrible racket while the old one will be nearly dead silent.

There are a lot of reasons for this, although much of it has to do with the restrictive cages on new fans to keep fingers away from the blades, while old ones had very open cages that would allow your entire hand to fit in. There real differences in blade design too, though(most of the old ones had steel blades that were pretty carefully balanced, while new ones have plastic blades that are cast as one piece and are "close enough"), but the point being that they managed to move a lot of air without waking the dead.

There's a company here in Kentucky called "Big *** Fans." They make 12'+, low RPM ceiling fans(mostly for industrial applications) that are noted for being nearly dead silent wile also moving huge volumes of air.

bunnspecial said:

Have you ever used a G5?

I have the front of one sitting about a foot and a half from my left ear as I type this.

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I have the same setup on my desk, main difference is, my "man-cave" is very quiet and still my G5 quad with its 10 fans does not make enough noise under normal use to bother me at all.

bunnspecial said:

Have you ever used a G5?

I have the front of one sitting about a foot and a half from my left ear as I type this.

The fans just aren't that loud in normal use. Granted I'm working in a lab with a lot of background noise due to ventilation(our HVAC system does a complete air change in the room roughly every 3 minutes) but I hear them unless I'm listening for me. The only time they get loud is if you're really crunching on it hard and heating up the processors, or if you spend a lot of time in Open Firmware, Apple Hardware Test, or some mode like that where the computer doesn't control the fans and just runs them at full blast.

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No, I have never used a G5. However, I do use G4s and I have used PCs I prefer fans running full bore, I dont for one minute like the Software controlled aspect of fans because i have find them in both PC and Mac setups to not really work at all. At full bore I know the fans are cooling the computer, Software controlled isn't good enough and makes the entire computer hot (PCs mainly, That's why I install SpeedFan on every Windows computer I have). Now my MDD, I added fans to the back because I dont like seeing CPU Temps at 131F adding the 2 fans in the rear (one running of 12V and the other running off the 4.7V by the fan plug by the CPU) makes the computer idle at 95F and raise to 110F under load rather than idling at 120F and rising to 131F+ under load. If i ran the main case fan on full bore the system never gets above 85F however the jet engine sound fills the entire house!

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weckart said:

So why would that be a problem since you think so little of quiet fans?
I have no time for noisy fans - I prefer efficient. Noisy fans are not necessarily better, just more attention seeking.

http://www.quietpc.com/casefans

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If a fan sounds like a Jet engine and prevents from doing anything not involving the computer (i.e. sleeping or watching TV) it makes those tasks impossible. That's why i added front and rear fans to the MDD to get the needed airflow without disturbing the entire house.

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bunnspecial said:

On a totally different scale, find an desk fan from the 1950s or earlier and compare it to a similarly sized fan made in the past few years.

Chances are, both will move a similar amount of air, but the new one will make a terrible racket while the old one will be nearly dead silent.

There are a lot of reasons for this, although much of it has to do with the restrictive cages on new fans to keep fingers away from the blades, while old ones had very open cages that would allow your entire hand to fit in. There real differences in blade design too, though(most of the old ones had steel blades that were pretty carefully balanced, while new ones have plastic blades that are cast as one piece and are "close enough"), but the point being that they managed to move a lot of air without waking the dead.

There's a company here in Kentucky called "Big *** Fans." They make 12'+, low RPM ceiling fans(mostly for industrial applications) that are noted for being nearly dead silent wile also moving huge volumes of air.

Click to expand...

I a few years ago bought an all metal desk fan after the one I had for 20 years or better shot sparks turning it on. It was a plastic blade fan. The all metal blade fan is quiet and most MUCH more air than the plastic one did.

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jbarley said:

I have the same setup on my desk, main difference is, my "man-cave" is very quiet and still my G5 quad does not make enough noise under normal use to bother me at all.

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where did u get the OS X theme

MatthewLTL said:

No, I have never used a G5. However, I do use G4s and I have used PCs I prefer fans running full bore, I dont for one minute like the Software controlled aspect of fans because i have find them in both PC and Mac setups to not really work at all. At full bore I know the fans are cooling the computer, Software controlled isn't good enough and makes the entire computer hot (PCs mainly, That's why I install SpeedFan on every Windows computer I have). Now my MDD, I added fans to the back because I dont like seeing CPU Temps at 131F adding the 2 fans in the rear (one running of 12V and the other running off the 4.7V by the fan plug by the CPU) makes the computer idle at 95F and raise to 110F under load rather than idling at 120F and rising to 131F+ under load. If i ran the main case fan on full bore the system never gets above 85F however the jet engine sound fills the entire house!

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Well, it's your hearing to lose.

I tend to trust the system engineers for most part, unless they give me good reason to think otherwise. My G5s idle at perfectly reasonable temperatures, and I'm not inclined to put up with the extra noise that running the fans at full blast would bring just to drop the temperature a few degrees.

The thermal engineering on the G5 is among the best of any computer I've encountered, and when all the fans get going at full blast(a rare occurrence) they make a racket that's just uncomfortable to be around. I don't see any point in using extra electricity and putting extra wear on the fan bearings just to drop the idle temperatures a few degrees.

(Once again, type with my left ear about a foot and a half away from the front of a G5 tower).