The PowerMac G5 ATX conversion

I have always admired the design of Apple’s most expensive computers, the PowerMacs’ and after that the Mac Pros’. These computers are targeted towards the power users such as members of the media-editing field where extreme computing power is required. The PowerMac G5 is based on the PowerPc processor architecture, this that means you can’t even run Windows on it since Windows is written for the x86 and x64 architectures.

The logic board of the G5 is specifically designed for the case and does not follow the conventional ATX form factor of motherboards so you cannot just install a regular motherboard.

Then I stumbled upon the hackintosh community InsanelyMac. Several members have modified their G5s’ to be able to fit an ATX motherboard. Most of them with laser-cut kits from a Great Britain-based company, The Laser Hive.

I began to scan the Swedish second hand markets after great deals for a G5 case. There where a few ads on Blocket most of them where priced at above 1000 SEK or sufficiently cheap but had tears and dents on them. Then I managed to find a guy who had two for sale but no price where stated. After a bit of haggling I got the price down to 500 SEK.

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These pictures are from the day I picked up the machine.
When I met up with the guy for the purchase I noticed that there was a large scratch at one of the side panels of the casing. I choose to disregard this since I got a great deal. There where some minor scratches elsewhere but if you account for the age of the machine it was well cared for

I later found out through the serial number behind the removable panel that it was the first generation of G5s’, released in 2003


Enough about that and on to the build. It took me about a month and a half from making the purchase to a finished case, and it has been a really fun process. For simplicity I have divided this post into the various steps in the build. In each step I will also try to tell you where I got the information about the necessary procedures. I will also show you what tools I’ve used. Bear in mind that this is not a tutorial but a buildlog.

The steps:

  • Disassembling the case
  • Cut the back of the case to fit the kit from The Laser Hive
  • Scavenge the parts from an ATX PSU to fit in the case of the G5’s PSU
  • Mount the new hardware
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One week later I received my order from The Laser Hive. I choose the PowerMac G5 full high-mount 120mm fan kit with the optional fan-overlay piece. I think that title has to come with a explanation:

  • Full means that the kit comes with all the necessary screws and is bundled with the motherboard plate.
  • High-mount means that the kit is meant to be used when you want to keep the power inlet of the G5 case
  • 120mm fan: you can either choose to keep the two 92mm fan setup at the back or mount a single 120mm fan. I choose the latter since most closed loop CPU watercoolers are 120mm mounted

What is not shown in the picture is the Twin 120 front fan support which I ordered as well so that I could mount two 120mm fans in the front of the case. You will see what the part looks like in other pictures later on.
What is also left out in the picture is the Front panel power and I/O G5 header to standard ATX pin cable which is necessary to be able to use the standard mounted front panel. These are custom made by G5 ATX cables housed in Spain. The cables are very high quality, they are sleeved and the ends are wrapped with heat-shrink tubing. It’s worth every penny since the cable is quite hard to make yourself. When looking for a G5 case, make sure that you don’t purchase the late 2005 model. Those have a different front panel port and are incompatible with the adapter cable.


Disassembling the case:

Guide for disassembling the case:

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The first picture is displaying all of the RAM sticks. Those are 512MB each, so that’s 3GB worth of RAM (remember this was back in 2003). Beside them is the speaker for the boot-chime and the video-card
The workbench where I did most of the work.
And the third picture shows the massive 600W Tesla power-supply.
The leftmost picture shows me holding one of the PowerPC processor with the large heat-sink mounted on top of it. The PowerMac sported two of these beasts.

Tools used in this part:


Cut the back of the case to fit the kit from The Laser Hive:

The cuts where made using a Clas Ohlson dremel tool with a Dremel(multitool) SpeedClic disc. I used the thickest disc available since it came with a starter kit for the SpeedClic mounting solution. Looking back, I would’ve probably used a thinner metal cutting disc for this since they give much cleaner edges. The key is to be patient when you are cutting. If you apply to much power to the multitool, the disc will shatter.

The guide for this is bundled in a USB-key with the kit from The Laser Hive. The guides are really well written and instructive and as they are The Laser Hive’s intellectual property I will not share them here. But you can find some documents at the website:

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Punching away some stand-offs that where in the way. Refer to the guide when doing this.
Inspecting the cut
This was before I made the cuts. Did some measurements

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Doing some touchup of the cut to get a straight line. It’s important that you take the appropriate measures in terms of security. I wore breathingprotection, safety glasses and earmuffs
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As you can see the backplate covers the whole cut-out so you don’t really have to worry about making clean looking cuts. I was just a bit careful since I wanted it to look great from the inside as well.

Tools used in this part:


Scavenge the parts from an ATX PSU to fit in the case of the G5’s PSU:

Warning!

You should avoid this if you don’t know your way around electricity. Human make great conductors. I’m not responsible for any damage to person or equipment. Think through what you are about to do before you do anything


Put simply, the idea is to cut the walls of an ATX PSU so that it will fit in the Tesla G5 PSU casing. You split the wires of a power cord and solder that to the wires coming from the inlet on the case and then plug it in to the ATX PSU inlet.
Here’s the guide:

Soldering the wires:

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I used a wire stripper to peel off the insulation off of the wires
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Fixate the wires to ease the soldering process. And don’t forget the heat-shrink tubes! You don’t need a heating gun in order to shrink the tubes, just use a regular lighter. Like this guy does here: how to replace the fan of your PSU

The fitting:

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Doing a test fit. Notice the insulation grade plastic between the wires and the heat-sink of the PSU. Also note the plastic separating the casing of the ATX PSU to the floor of the G5 casing. This plastic came with the case.
I had to cut the original hole to the right in order to fit the large 24-pin cable and the PCI-E cables

Tools used in this part:


Mount the new hardware:

We have now arrived to the fun part of the process. I didn’t purchase any new hardware. But I felt like replacing my Fractal Design fans that came with my previous case since they are sleeve bearing fans. I managed to find fans that go quite well with the color coding in the rest of the G5. They are called Scythe Gentle Typhoon, and I choose the 800RPM ones.

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Here you can see the dual 120mm front fan support I talked about as well as the front panel cable. The front fan support is really well engineered. And it blends in really well behind the mesh at the front of the case
Test run. Everything seems to run smoothly. At this stage I noticed that the fans where spinning at 100% (12V), so I used resistor adapter cables to lower the noise.
Replaced the cooling paste since that haven’t been done since I purchased the hardware three years ago. Also replaced the CPU fans to a push/pull configuration. I used a PWM cable with Y-connectors to connect both of the fans to the CPU-fan header

Some notes about what you see in the photos

In the first photo you will also see how I mounted the original harddrive-cage to the top shelf. I drilled three holes in the shelf that lined up to the holes on the top of the harddrive-cage. Then there was just a matter of fixating it using the original screws and a Philips-screw bit (since the area is to short to use a screwdriver).

What you don’t see in any of the photos is the fans responsible of cooling the the power-supply. I replaced the original 60mm fans with Noctua ones, I choose to spend a little more on these fans since cheap small fans tend to be a bit noisy. The front fan support kit came with a mounting solution that made the whole mounting possible since the standard mounting solution would make the mounting of the PSU impossible. The fans are connected to a Molex cable via a resistor adapter cable. I intended to use the internal fan port of the ATX power-supply at first. So I soldered the cable from the PSU-fan to a regular fan connector and then connected that to a Y-cable. But that solution didn’t produce enough power for the fans to even start spinning, so I had to abandon that idea.

Per request, here’s my hardware specifications:

Comments: The major part of my hardware is over 3 years old. I purchased the SSD and the GPU last summer. I had some trouble with performance in Battlefield 4 but made the upgrade to Windows 8.1 since Dice stated the game has better support for it. After the upgrade I noticed a quite large increase in performance.

And the temperatures?

Hardware Temp in idle Temperature ingame
CPU 45° C 61° C
GPU 48° C 80° C
SSD 30° C 35° C
Motherboard 46° C 60° C
AUX Motherboard Sensor 45° C 107° C

Comments:

First thing: yes, the SSD has a temperature sensor. I choose to include this in the table since it shows that the overall temperature in the case is increased during load. Even though the SSD is located directly next to a intake fan. If you look at the photo beneath this paragraph you will see that the hot air will gather above the GPU and is only pushed out by the GPU fan. 80° C is a decent temperature for a GPU at load but this can cause problems in the summer when the room temperature is higher. A countermeasure would be to install a PCI-socket mounted fan, but I haven’t found any that are not low-quality or noisy.

About the “AUX” sensor reporting 107° C is quite alarming. This seem to be a misreading but is worth investigating. More about the misreadings here: AUXTIN temperature what the heck?


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Here’s the final result. This is as good as it gets in terms of cable management. The cables from the modular ATX PSU is simply too short for these kind of mods. Do you remember that I lead the cables from the back of the G5 PSU casing to the middle of the PSU casing where the cable holes are located? This procedure cut 15 cm off of the cable length outside the PSU casing

Notice the G5 CPU cover-plate? I taped it to the wall using double sided tape.

Here’s another minor setback. The back of the GPU is tucked tightly against the hard-drive cage.

The final result:

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Acknowledgements

  • David at The Laser Hive. Without your expertise in the area and the well-written correspondence this mod would not be possible
  • My grandparents (on my mothers-side) for taking me to a distant suburb of Stockholm so that I could purchase the case. And thanks again to my grandfather for providing me with valuable tips about working with metal which I had no past knowledge of.
  • My father for aiding me with the electrical bits and for giving advice about the build in general.

The future for this workstation:

At some point I will probably try to dualboot Mac OSX together with Windows 8.1. It’s seems much simpler now than when I looked at it a couple of years ago.

I’m currently searching on the second hand market for a 27″ Apple Led Cinema Display or the 24″ one (not the Thunderbolt models). As you can see in the photo below I have also purchased a Mac keyboard. I did this because they go well with the case and provide a great typing experience.

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Resources

That’s it for today! You are welcome to contact me on any Social media or through the email-form if you have any questions.

Take care