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Comprehensive Guide to Converting G5 Quad to Air Cooling

This guide is amazing. I bought a cheap "dead" quad g5 on Facebook marketplace a while back that I always wanted to try and fix. I stumbled upon this guide and figured it was worth a shot. I bought all everything that I didn't have currently that the guide suggested on amazon. Everything I needed arrived this afternoon. I followed the guide to a tee, and it took me about 2 hours to complete. The hardest part was disassembling and getting out the lcs. After putting in the air coolers and reassembling, to my surprise it started up.

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@jacksonmf, I am glad that the guide was of value to you and that you now have a cool, quiet Quad, and an air cooled one at that. Never again will you need to worry about LCS failures or offensively loud CPU fans.

I am constantly trying to improve the guide. If you have any thoughts/suggestions in this direction, I would love to hear them.

Either way however, I am glad that the guide helped. Enjoy your revitalized Quad!
 
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mac57mac57 said:
@jacksonmf, I am glad that the guide was of value to you and that you now have a cool, quiet Quad, and an air cooled one at that. Never again will you need to worry about LCS failures or offensively loud CPU fans.

I am constantly trying to improve the guide. If you have any thoughts/suggestions in this direction, I would love to hear them.

Either way however, I am glad that the guide helped. Enjoy your revitalized Quad!
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I'd recommend having a page at the front with the complete parts list including the spacers used. That's just being nit picky. It's a great guide!
 
Amongst the "goodies" I picked up a few days ago, along with the dead Quad and the two 20" Apple Cinema displays, was a copy of Microsoft Virtual PC v7 for Mac (PPC). I installed it today onto my Air Quad, and if one truth shines through, it is that there is nothing like Microsoft for bringing a Mac to its knees. I have always said this about Microsoft Office, but now I can report that it is true for Microsoft Virtual PC as well.

Virtual PC kept one core at least, at almost all times, running at 99%. CPU temps were nicely controlled, never leaving the mid 60s, but Mac OS X, unaware that it wasn't in charge of the cooling anymore, ramped up the CPU intake/exit fans to 3000 RPM and kept them that way as long as Virtual PC was running. Rather more noise than I would like!

So... I am going to have to run the intake/exit fans through another of those third party fan controllers with speed adjustment dials, the same as I have on my LCS-cooled Quad. That way, I drop Apple out of the cooling loop and all will be well/quiet again.

Thinking of Virtual PC? Don't do it unless you like fan noise!
 
By the way, about improvements to the guide, it says you can undo the screws on the processor card in any order you wish, but that's not really the case.

You want to undo the four screws that put pressure onto the card so that the CPU is flat against the heatsink in a criss-cross pattern, and gradually, few turns at a time. Undoing it in a different way risks cracking the CPU die. Same for tightening screws.

In general, with any heatsink half-mounted, uneven pressure on the die can lead to a cracked die.

I would also be a bit worried about the new heatsinks potentially cracking a die when the G5 is moved from place to place. If you aren't all too gentle when you put it down, you can transfer a whole bunch of momentum to those massive heatsinks, which just happen to be sitting on two screws, forming a convenient axis of rotation and potentially allowing the heatsinks to transfer all that momentum directly to the CPU dies. It's not that big of a deal, but I'd personally be a bit worried about it.

My current best idea for how I would address this is cutting out a thingamajig that would hold the heatsinks in a locked position out of a few layers of cardboard stacked together and double-sided-taping it to the bottom PSU plate thing. Laser-cutting out of metal would probably work too, although cardboard would probably have less bounce, meaning it would absorb some of the momentum through deformation. Wood would probably be as good as cardboard, and have the distinct advantage of looking sick.
 
mac57mac57 said:
Thinking of Virtual PC? Don't do it unless you like fan noise!
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Virtual PC is an interesting case. It is, I think, one of the only pieces of MacOS software that is not significantly faster on a G5 than it is on a G4.

This is because on the G4 it leverages the little endian instructions it has to greatly speed up emulation while the G5 omits these instructions entirely and is strictly big endian only, which means a lot of overhead due to byteswapping.

When I tested this with the 7zip benchmark, a 2.5GHz G5 just barely inched ahead of a 1.4GHz G4.
 
Thanks @Nullcaller, good comments. I will look through the section in question and tighten it up a bit. Certainly I always undo the screws in a criss cross way - I THOUGHT the guide said that, but I will check and reissue as needed.

Honestly however, in all the years that I have been working with PCs and Macs, and that is a lot of years, I have never had a die crack.
 
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Nice, thanks, @mac57mac57! If you always undo the screws in a criss cross way, you'll certainly never have a die crack :) And, like, at some point, for anyone who've dealt with enough electronics, it just becomes an instinct that you don't feel like you have to explain. But yeah, it's better to reiterate this.

I've looked through the guide another time to check, but couldn't find anything about that, except it saying that you want to undo the four screws holding down the processor package last. I apologize for raising a false alarm if it does say the thing, and I'm just blind, though, cause my brain does that from time to time. Powers of observation, you know.
 
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jacksonmf said:
This guide is amazing. I bought a cheap "dead" quad g5 on Facebook marketplace a while back that I always wanted to try and fix. I stumbled upon this guide and figured it was worth a shot. I bought all everything that I didn't have currently that the guide suggested on amazon. Everything I needed arrived this afternoon. I followed the guide to a tee, and it took me about 2 hours to complete. The hardest part was disassembling and getting out the lcs. After putting in the air coolers and reassembling, to my surprise it started up.

View attachment 2530164
Click to expand...
Glad to read this...I too have a Quad lying around that I've been wanting to tinker with, but the LCS has scared me as trying to re-tool that is way above my skill level. This guide, though, sounds like something I can tackle, so I may try to carve out some time in the next few weeks to finally give it a shot. Thank you to Michael for all of his efforts in producing this amazing guide!
 
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Question, and apologies in advance if this is already answered in the guide, but…does the G5 aluminum panel covering the original LCS fit back over the CPU bay after this modification, or does the new air-cooling system prevent that from being reinstalled? Just would love the system to look as “normal” as possible, but not a big deal if the addition of the fans keeps that from being possible. Thanks!
 
dpfenninger said:
Question, and apologies in advance if this is already answered in the guide, but…does the G5 aluminum panel covering the original LCS fit back over the CPU bay after this modification, or does the new air-cooling system prevent that from being reinstalled? Just would love the system to look as “normal” as possible, but not a big deal if the addition of the fans keeps that from being possible. Thanks!
Click to expand...
Yes it does fit! My PCQ (PC Cooler Quad) has its original cover panel reinstalled over the coolers, and there's even a few mm of clearance so it doesn't rub against the coolers.
 
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