PowerMac G5 ATX Gaming PC Case Mod

Patrick Robert Doyle
11 min readFeb 6, 2021


Before we get started: This isn’t a G5 Hackintosh transformation. With a 16-inch MacBook Pro as my ‘daily carry’, and 5 functioning Macs within 5 strides of where I’m writing this, I don’t need yet another one to add to my already complex polyamorous mac-relationship. But I do need to spice things up a bit in the gaming-room with a PC.

An Apple PowerMac G5 surrounded by modding components

Whilst I usually write about design, UX, and other Totally Cool things, there’s still a nerd living somewhere deep in my personality. This article is a holiday from the usual UX articles by me.

If, like me, you fell in love with an aluminium metal box in the mid-2000’s and spent many of the following years dreaming of the day you could drop $2,000+ on something that lives under your desk, you’ll understand how excited I was to invest some of my COVID-time to fulfil this teenage fantasy.

Here’s how I gave an Apple Power Mac G5 a 15-year upgrade by transforming it into an ATX gaming PC.

Sourcing a G5 case

Back in the mid-2000s, a shiny new anodised aluminium G5 would cost you a minimum of $2,000. In 2020, I picked up this old man on Ricardo (Switzerland’s version of eBay) for 100 CHF (~$100 USD).

Whilst I don’t know what sort of life my G5 had before I dragged it’s hefty weight back to my place. I like to think it had an exciting career working hard on TV productions, designing posters, or perhaps photography for a estate agent who specialises in grain silos converted into homes. Alas, it was missing come parts that allowed a glimpse of it’s former life. Of course, for modding purposes it doesn’t matter if it’s in a working as long as the case looks healthy.

A screenshot of eBay showing G5s
eBay is your friend for sourcing a G5 case, unless you have one of those real friends with a spare G5.

Case parts list

Because I’ve frequently fantasised about homing a G5 since my school years, the last thing I dreamed of doing is hacking together a Frankenstein’s G5 held together with duct tape and wishful thinking. Doing a high quality job of the mod should mean a long and loving relationship with this case, even as its guts get replaced with new hardware.

An Apple PowerMac G5 surrounded by modding components

Two suppliers have been invaluable during this project:

The first is The Laser Hive in the UK who designs and fabricates custom hardware for case modifications, including a variety of G5-specific parts. They provide cutting documents for some of the parts used in this article, and an online shop where I sourced many of the pieces.

The second is BlackCH Mods who sells an adapter for the power button and front panel so it can be used with ATX motherboards.

Most of these parts are either optional or you can find your own solutions, but because I’m a caring lover and I want the option upgrade the PC components in the future, I splashed out on the following parts:

If you only spend money on 1 thing, the bare-minimum has to be the ATX conversion kit or at least a motherboard tray. The amount of time, pain, and frustration saved by the prefabricated metal back-panel and perspex motherboard tray kept this build an enjoyable one.

G5 modding components from The Laser Hive
The pieces I purchased from The Laser Hive, a little expensive, but worth the investment.

For PC parts, I’ll be transplanting the organs of a relatively new gaming PC I inherited from a friend who no longer needs it, but I plan to upgrade some core components shortly.

1. Gutting the G5

Apple takes as much care designing the inside of their hardware as they do on the outside. The G5 was the first desktop machine Apple designed with a foundation for airflow and cooling. Hence the 4 partitioned levels where air passes front-to-back over the CPU, expansion slots, DVD and hard disk drives, and (hidden under a shelf under the CPU) PSU separately.

The internal view of a PowerMac G5

Removal of the existing components is relatively straightforward once you get passed the first hurdle: How do you get that bloody CPU cover off!?

On the top side of the CPU cover, you’ll find a tiny grey plastic bolt which can be removed with pliers and patience, allowing the cover to slide off. There, I just saved you 30 minutes of confusion.

A photo showing the G5 CPU cover locking mechanism

Once you’ve removed most of the G5 components, you’ll eventually end up asking “How the heck do I remove the upper shelf?”

DON’T cut this piece out, as you’ll need the locking mechanism to keep the case closed. Unless you like the duct-tape-on-anodised-aluminium aesthetic; who am I to judge?

The magnificent Eelhead of tonymacx86 to the rescue with a step-by-step guide.

Make sure to keep locking mechanism safe for reinstallation later.

Remove everything else, but keep hold of the upper shelf if you plan to install something in the 5.25" disk drive bay (which I do).

PowerMac G5 components removed from the case
Not pictured: 15 years worth of dust.

It’s also worth holding onto the G5’s hard drive enclosure with the anti-vibration screws if you plan to house 3.5" drives.

A photo of the G5 hard drive bays
Keep the hard drive bay to one side if you plan to house a couple of 3.5" drives.

2. Fitting the ATX back panel

Unless you plan to keep a beautiful empty aluminium box as a showpiece,it’s time to mount that ATX backplate.

I chose to purchase the The Laser Hub’s G5 ATX backplate as it includes all the correct mounting points for not just the expansion ports to hold my heavy graphics card, but also a nice spot for the PSU.

Most other G5 conversions rest the PSU at the bottom of the case, and either cut a horrible hole in the bottom for the power cable to fit or do some crazy wiring-magic/fire-hazard to connect it to the existing power socket. But with aesthetic, reusability, and safety in mind, mounting the PSU directly to the back of the case seems more sane.

The Laser Hive kindly provide a step-by-step guide to fitting the ATX backplate, but the tl;dr is:

1 — Place the backplate on the back, and mark where to cut out the existing casing.

2 — Use a Dremel (or other rotary tool) to cut out the marked areas (IMPORTANT! Don’t cut off too much, you can always remove more later.)

A Dremel rotary tool
Other brands of rotary tools are available.

3 — Fit the backplate with the screws provided.

4 — Photograph the before and after for your How-To article.

The before and after state of installing the Laser Hive ATX back panel
[Chef’s kiss emoji]

3. Attaching new motherboard mounting points

Unfortunately the existing mounting points don’t fit either standard ATX motherboards or the correct placement in the case. If you haven’t already removed them, you can do so by lightly tapping them to one side with a hammer.

Some tutorials show you how to attach your own motherboard mounting points with an assortment of sockets, glue and patience. But if, like me that doesn’t sound like a good time, The Laser Hive’s kit (I promise I’m not sponsored by them… unless they want me to be 👀) comes with an acrylic tray that uses existing points in the G5 case to adapt the layout to ATX mounting without any drilling or gluing.

The Laser Hive ATX motherboard tray
This fancy piece of plastic saved me hours of frustration.

I highly recommend this technique over the alternatives, both for time and frustration of getting it right, but also it doesn’t damage the case’s aesthetics.

4. Refitting the shelf (Optional)

Voila! At this point you have a converted Apple PowerMac G5 ATX case ready to home your new PC.

If you’re using an M.2 SSD without a need for additional 2.5” or 3.5” drives, there’s nothing left to do but install all of your PC components.

An old PC and Apple PowerMac PC side-by-side
I’ll be transforming the G5 into a gaming behemoth once I get my hands on Nvidia’s latest hardware, but in the meantime I’ll be transplating older parts from another PC.

However, my build is a little atypical.

I plan to use the existing disk-drive bay to house USB 3.0 ports accessible from the front of the case, hold a couple of 2.5” SSDs, and to help mount a beefy CPU watercooler radiator.

Before reinstalling the shelf it’ll need a couple of modifications.

First some space needs removing to accommodate the new PSU. Honestly, I just mounted the PSU and eyeballed how much of the shelf to cut away + a little extra to thread cables between the upper and lower partitions.

In-line with Apple’s original design philosophy for a cool but quiet workhorse, I will be water-cooling the CPU, and mounting the radiator to the front of the case.

The Laser Hive to the rescue again, with a custom mounting part. I went for the 2 x 140mm.

The Laser Hive fan bracket
I’ll be mounting a 280mm CPU cooler to this in the future.

This adds a few extra steps. The first it to measure, mark, and drill holes in the upper shelf to mount the bracket to, before refitting the shelf.

Reinstalling the shelf is a matter of wiggling it back into place and reapplying the screws.

The G5 shelf shown with a modification to fit the PSU
The shelf back in place, with space cut for the PSU, and the fan bracket installed.

5. Reinstall the locking mechanism

Unless you plan to leave the G5 sideless (eww), simply reverse the instruction you followed to remove the locking mechanism. Pay close attention to which way around the spring-clips are reinstalled. You want it so the latches are held firmly in the sliding mechanism, otherwise the clips will fall out.

6. SSD Mounting and Super Secret USB Ports (Optional)

Back in 2005, data was held on spinning metal disks that were read by articulating arms. Crazy right? These ancient metal blocks were bigger than today’s motionless SSDs, where data is held by… magic? Apple’s industrial designers neglected to include anywhere for these future yet-to-be-imagined components to live.

Fortunately, Silverstone’s FP55 5.25-inch to 3.5-inch bay conversion kit includes internal mounting points for two 2.5-inch SSD drives, whilst providing additional mounting points for a 3.5-inch external bay.

Because the G5’s single front-facing USB port is handicapped to pathetic USB 2.0 capabilities, I wanted a way to access 3.0 speeds without launching an expedition into the cable forest at the rear of the case.

There are plenty of USB 3.0 brackets for 3.5-inch bays. I went for the Cooler Master Bezel USB 3.0 3.5-inch drive bracket, for no particular reason other than it was available.

A USB hub
This is probably the only (maybe) unique part of my build.

Liberating the screws and silver surround from the G5’s former disk drive, and combining them all together with the USB drive bracket, 5.25-inch to 3.5-inch bay converter, and fitting a 2.5-inch SSD drive, the self-contained unit slides and locks into the existing drive bay like a dream.

A USB drive plugged into a modded G5 PowerMac
Who even uses physical media anymore?

7. The tricky situation of the power button

Light googling will uncover plenty of novel and/or hacky solutions to overcoming the problem of Apple’s proprietary connectors for switching on your transformed G5. But I simply couldn’t bring myself to altering the case’s aesthetics.

Just when I thought defacing the front-panel may be necessary, I happened upon BlackCH’s G5 Front Panel to ATX Adapter Kit. A beautiful plug-and-play converter and braided cable that fits into the original I/O connector for the front-panel!

A custom cable made by BlackCH for converting the G5 PowerMac to ATX
The modding community never fails to amaze me.

And as a bonus, it restores access to the USB 2.0 port, power LED, and headphone jack. The only peripheral left inaccessible is the Firewire port. Oh well~, was anything of value lost?

The cable mod installed in the G5
Couldn’t be happier to restore use of the front I/O panel.

8. Installing the PC components

Right now the Apple G5 case is 100% prepared to live it’s life as a PC.

For the moment I’ll move some legacy components from my old PC to the new case, so I can still kick ass in Overwatch whilst waiting for the new parts to arrive.

An Apple PowerMac G5 with ATX components installed
Not as elegant as Apple’s original internal design, but far more practical.

The 5.25-inch hard drive will be replaced by SSDs, but in the meantime I glued some rubber feet to the repurposed hard drive enclosure and placed it on the bottom of the case. Not a bad solution for those who need somewhere to keep their drives, but I wouldn’t call it secure.

The hard drive enclosure is resting at the bottom of the case
Whilst I’m only using the HDD enclosure as a temporary solution, it could easily become more permanent.

Final thoughts

I love it!

A teenage dream completed, and I couldn’t be happier to have this new resident living under my desk. At this point, I can’t think of anything I’d have done differently, and I’m hyped to get the CPU watercooler, and fresh components installed when they arrive.

An ATX converted Apple PowerMac G5 sitting under a desk

If you have any questions about this PowerMac G5 ATX case mod/transformation or you’d like to purchase a pre-built ATX-ready G5 case, you can always find me on my Twitter account @TeaPowered.

Update: Winter 2020/21

✅ M.2 SSD
✅ Second SATA SSD
✅ CPU watercooler
✅ Dust filter

Although the existence of purchasable RTX 3080 and 3070’s were apparently propaganda put out by Nvidia, I was lucky enough to hunt down an Asus TUF RTX 3070 just after launch.

A PowerMac G5 with an RTX 8070

The G5 may be already running hardware thousands of times faster than when it was born, but that didn’t stop me dropping in an even faster M.2 SSD (Corsair MP600).

A PowerMac G5 with an RTX 8070

Whilst diving back into the G5’s innards, I swapped the temporary HDD sitting at the bottom with a second SSD (a Samsung 860 EVO Basic if you’re interested) that now lives in the disk-bay-come-USB/SSD-hub, freeing up space for the planned CPU watercooler.

An Apple PowerMac G5 sitting under a desk

Speaking of which, fitting the Arctic Liquid Freezer II (280mm) took a little extra work, with access to the mounting points on the fan bracket limited to a 2cm space. But with the CPU watercooler finally fitted, this build is complete.

Now that the remaining noise-makers have been swapped for more noise-considerate parts, the G5 runs completely silent under normal use, with a little fan noise at full-tilt in Cyberpunk 2077.

As any nerd with fidgety hands knows, this build will keep evolving, but I don’t plan on any hefty upgrades until I eventually give into dropping cash on an AMD Ryzen.

One last thought…

Something that is often cared for and enjoyed so much is usually given a name, I’m thinking either ‘PowerMax’ or ‘Max Power’.



Patrick Robert Doyle

A tea drinking Brit who moved to Switzerland, writes about UX design and takes photos — Head of Design at gowago.ch