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Running PowerMac G5 Without Radiator Fans

onesimus

onesimus

Experienced Member
Joined
Jan 14, 2023
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144
Location
Turtle Creek (Madison), West Virginia
I just received a PowerMac G5 with the dual processor setup today from eBay. It does work, but for whatever reason, the fan assembly that cools the water cooling area or whatever you want to call it is gone. So in theory, if I run it, the only cooling for the processor would be the rear exhaust fan and there would be no other fans cooling the radiator.

My question is: how dangerous is running it like this? Would it run too hot to install System 9 or OSX Leopard? Is it safe to leave on for a few minutes or should I pretty much just not power it on at all. I got a pretty good deal on it, so I'd rather not destroy it. I have a fan assembly on the way but I'm itching to use it right now. It's a real unit.

Also, if this is the inaugural thread for this sub-forum, I am honored, lol.
 

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DO NOT RUN IT WITHOUT FANS. Buddy (from vogons) learned that hard way, and destroyed the processors and heatsinks. And remove those heatsinks and look them over well, they love to corrode.

As for replacements, hear EVO 212s work pretty well, but you will have to elongate the holes of the AM3 bracket or AM4 brack, forget which. Just got done doing full day at work plus delivery on way home so brain is mush. I will try to get you details tomorrow. Now considering there are 20 at least versions, far as I remember it was the older original as newer the heatpipes are a little taller. I remember you have to file off round 1mm off the top for the side panel to fit.
 
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You're missing more than just the fans.

There are studs missing on both coolers in the middle where they meet at the base. Makes me wonder what's missing on the back side. You're also missing the clear plastic cover that covers that entire CPU/RAM area, if you didn't remove it to take the picture. DO NOT operate the machine with those studs missing. The processor+heatsink module is very heavy, and those studs being missing will allow heat cycling and vibration to work the processor modules out of the sockets on the logic board.

Also, if the previous owner didn't recap the power supply, expect to have to do so sooner than later. I would recommend running it until it dies, because the power supply is extremely difficult and dangerous to remove. It gives even Mac veterans like us a ton of trouble. The dangerous part is that the logic board has to be removed in some models, and these boards used the early TERRIBLE ROHS solder that is subject to failure just looking at in a way that doesn't please it. Just slightly flexing the logic board can kill it. Recapping the power supply is also very difficult without the proper equipment due to the large power planes. You need a board preheater or a hot air station to keep the board warm enough to melt the solder to remove the capacitors. I think it was about $60 in just capacitors when I did mine last year.
 
NeXT said:
The cooling is required. The Environmental Monitor will also be very unhappy if it can't detect the fans.
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Good to know, I do have a solution on the way, at least. I also thought about plugging a sata power to fan converter into one of the free sata connectors but from what you're saying it sounds like that may not be a good route.

GiGaBiTe said:
You're missing more than just the fans.

There are studs missing on both coolers in the middle where they meet at the base. Makes me wonder what's missing on the back side. You're also missing the clear plastic cover that covers that entire CPU/RAM area, if you didn't remove it to take the picture. DO NOT operate the machine with those studs missing. The processor+heatsink module is very heavy, and those studs being missing will allow heat cycling and vibration to work the processor modules out of the sockets on the logic board.

Also, if the previous owner didn't recap the power supply, expect to have to do so sooner than later. I would recommend running it until it dies, because the power supply is extremely difficult and dangerous to remove. It gives even Mac veterans like us a ton of trouble. The dangerous part is that the logic board has to be removed in some models, and these boards used the early TERRIBLE ROHS solder that is subject to failure just looking at in a way that doesn't please it. Just slightly flexing the logic board can kill it. Recapping the power supply is also very difficult without the proper equipment due to the large power planes. You need a board preheater or a hot air station to keep the board warm enough to melt the solder to remove the capacitors. I think it was about $60 in just capacitors when I did mine last year.
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I do have the plastic piece, makes sense about those missing studs though, I need to find a solution for that for sure. Man, this is starting to sound like I unknowingly jumped into a world that I wasn't prepared for! Oh well, though, they are always the best of learning experiences!
 
twolazy said:
DO NOT RUN IT WITHOUT FANS. Buddy (from vogons) learned that hard way, and destroyed the processors and heatsinks. And remove those heatsinks and look them over well, they love to corrode.

As for replacements, hear EVO 212s work pretty well, but you will have to elongate the holes of the AM3 bracket or AM4 brack, forget which. Just got done doing full day at work plus delivery on way home so brain is mush. I will try to get you details tomorrow. Now considering there are 20 at least versions, far as I remember it was the older original as newer the heatpipes are a little taller. I remember you have to file off round 1mm off the top for the side panel to fit.
Click to expand...
that would be amazing if am3 or 4 brackets would work, even if with a little modding. If that's the case I'd just try to completely go that route for sure. For noise if anything. I hear these are super loud, haha.
 
onesimus said:
Man, this is starting to sound like I unknowingly jumped into a world that I wasn't prepared for! Oh well, though, they are always the best of learning experiences!
Click to expand...

Apple machines in general are an expensive hobby, but the G5 line is in their own category from them being a box of lemons. From the overall design faults, ROHS solder problems, capacitor issues and the heat and power consumption of the G5 CPUs themselves, they're not fun machines to maintain. It's a good thing that you didn't get one of the liquid cooled models, as those add an extra layer of complications.
 
GiGaBiTe said:
Apple machines in general are an expensive hobby, but the G5 line is in their own category from them being a box of lemons. From the overall design faults, ROHS solder problems, capacitor issues and the heat and power consumption of the G5 CPUs themselves, they're not fun machines to maintain. It's a good thing that you didn't get one of the liquid cooled models, as those add an extra layer of complications.
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Yeah I certainly am glad of that now since it gives a bit of flexibility in cooling solutions. If I had it to do over again I would probably go with a g4, even though from my perspective it's not exactly easy on the eye. It's seemingly a bit simpler to deal with in a variety of ways, has access to classic macos running natively, and most likely has better compatibility with the entire range of legacy ppc software (although I haven't really investigated this yet). I am a complete ppc noob and from the outside looking in, the G5 seems like a pretty cool machine. I found a good deal and just went for it before doing the due dilligence. The G5 still has some charm in my eye, though, even though I can't quite put my finger on exactly why.
 
I would definitely recommend a G4 over a G5. Aesthetic issues aside, they were a lot more reliable and ran cooler and quieter.

If you still need the grunt, there were several dual processor models, and some of the single processor models could be upgraded to dual processor models by swapping the CPU board out.
 
The most reliable / powerful Power Mac G5 was the 2.3ghz dual core (single socket) model, from what I understand. I have one and haven't had any trouble with it, it's almost 20 years old now. Air cooling, SATA for storage, PCIe... just about the best feature set without having the water cooling issues of the 2.5ghz quad core.
 
No, actually, the DP 2.3 was better than the DC overall for reliability (at least for the service statistics that existed). On the other hand, the DC 2.3 is still more reliable than most, and is slightly faster.

That said, the Quad generally had the best track record for the LCSes, but only the Delphi v1. The Cooligy v2 has its own irregularities. I have spare Delphi modules and those can replace the Cooligys with a little fiddling (the frame won't go back on but you don't need it). http://tenfourfox.blogspot.com/2021/07/and-now-for-something-completely.html
 
Do you guys think the sata power to regular modern fan solution is viable? I have a dual fan oem assembly on the way, so it's just a temporary solution. Still though, is it viable enough to work with it if I fit it good and everything?
 
onesimus said:
Do you guys think the sata power to regular modern fan solution is viable? I have a dual fan oem assembly on the way, so it's just a temporary solution. Still though, is it viable enough to work with it if I fit it good and everything?
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UPDATE: This seems to work in a pinch, got a big fan going, full speed all the time. It's certainly in a ...rigged fit to say the least, but it's in there nonetheless.
 
I have a PowerMac G5 DP 2.3 GHz that I purchased in 2006. It is still going strong. The DP is air cooled, vs. the Quad, which is liquid cooled. I agree with @GiGaBiTe, the Quads are tough to maintain when they break down.

I also have a Quad, and it runs fine, but the cooling is slowly failing and the fans run faster each day it seems. CPU temperature are kept perfectly in range, but the fans are rolling at about 2400 rpm to accomplish that, which makes a bit more noise than I like.

So... the DP, air cooled and whisper quiet, is the main G5 I use. The Quad is a work in progress... the process to flush and recharge the coolant (which I suspect is needed to lower the fan speeds) is DAUNTING, most definitely not for the faint of heart, and again as @GiGaBiTe points out, the probability of damage is high, given how "delicate" this brute of a machine is.

If you are thinking of getting a PowerMac G5, steer clear of the Quads and go for a 2.3 GHz DP. It is nearly as fast, much more reliable and doesn't command the price premium that Quads still get.
 
I'm curious if the G5s are very interesting. I have a G4(my "token mac"), but I'm curious if I need a G5.
 
hunterjwizzard said:
I'm curious if the G5s are very interesting. I have a G4(my "token mac"), but I'm curious if I need a G5.
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The G4 and G5 clock for clock are not very far apart. Where the G5 edges the G4 out is the FSB, the G4 has a 167 MHz FSB while the G5 is 667 MHz. The G4 is heavily constrained by bus bandwidth, where the G5 has a lot more headroom, which is where you see massive performance gains. Graphics and video are going to be much faster on a G5.

But that doesn't change the fact that G5 machines are a glass house. They're extremely fragile because of the ROHS solder used, and just slightly flexing the board can kill the machine. Since they also have issues with capacitor plague in the power supply, it's inevitable to insult the logic board to get the power supply out of the bottom of the case to repair it. This is how my dual G5 2.0 died. Fixed the power supply but destroyed the logic board.
 
The G5 is what you get when you try to build an "affordable" (gotta use quotes because it's a high-end Apple machine) consumer computer out of parts that were basically snatched off a mainframe assembly line. When you look at the procedures that are expected to "properly" service a G5 it becomes pretty clear how wide the gulf is between them and what Intel was selling at the time. I mean, criticize the Pentium 4 all you like for being a not particularly elegant or well executed architecture, but Intel was able to package it in such a way that your average Jolt Cola-addled gamer boy could usually manage unpack one of Intel's "Boxed" CPUs, drop the chip into the ZIF socket with their jittery ham-hands, crush the supplied cooler down on it, and end up with a system that works perfectly fine. G5s do *not* tolerate that kind of treatment.

It's kind of like the difference between servicing a Chevy Camaro and a Bugatti Veyron, except it's worse because this is a Veyron that retained all the overly complicated service rituals and fragile design of the million dollar version but was built at a price to try to directly compete with that Camaro. (Or, let's be generous, maybe the cheapest trim of a Corvette?) These were machines that were built out of deperation, and it shows.
 
Its a mixed bag. The G5s were expensive, and some of them were very problematic, particularly the G5 Quad with the liquid cooling system.

However, the late model 2005 air cooled Power Mac G5 DP 2.3 GHz is a solid machine. I have been running mine since 2006 and it continues to deliver stellar service to this day. At this point, it runs an internet-visible Gopher server 24x7x365. Solid as a rock, and runs cool too for G5s... high 40s except under heavy load.

The G5s ARE interesting! I would state unequivocally that my G5 DP 2.3 GHz is my favorite machine. The G4 Cube is the runner up.
 
mac57mac57 said:
The G5s ARE interesting! I would state unequivocally that my G5 DP 2.3 GHz is my favorite machine. The G4 Cube is the runner up.
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I worked on the G5
The statement that "These were machines that were built out of deperation" is something someone with no knowledge of their
design process and a Apple hater would say. Moto had left the market for embedded PPC, IBM would do the same. PA Semi
had a portable low power processor but was stuck with no customers when Apple made the x86 switch after I had left. The
core of the PA people came to Apple, and is why they are using M-series ARM CPUs of their own design after Intel proved
they had no interest in changing anything not needed by Windows.
Jobs' decree about fan noise made a machine with 125 watt processors difficult to package.
I will agree that the power supply placement is awful, especially if the box sat on a rug, which most did.
 
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