The PC case has evolved over the years but it's still largely the same deal. You pick up a standard ATX mid-tower chassis, install a few fans and an RGB-enabled liquid AIO CPU cooler, and call it a day. Having built more systems than I can recall, it was time for something a little different. The Power Mac G5 tower is a gorgeous aluminum chassis with an expansive internal space, high-quality build, and excellent airflow support. Something I failed to note in my introductory piece on Project G5 is my desire to own a Power Mac G5 as soon as I spent time using it in school.

Souring and prepping all the required parts

Creating a blank canvas for Project G5

The Power Mac G5 is no longer made nor sold so you'll need to hit classified websites such as eBay to source a second-hand unit. It's best to check for damage and other issues that could hamper your build process or the result. You could go for a Power Mac G5 or Mac Pro as the process and result will be similar. Though the unit I managed to get hold of has a few knocks and scratches, I believe it adds character. As covered in my earlier piece, here's everything that's going inside the Power Mac G5:

This project would have progressed nowhere without the excellent David from The Laser Hive. David sells full G5 conversion kits and accessories that make the entire process painless with full instructions that make them as simple as putting together IKEA furniture. I'll be using the G5 Full ATX conversion kit with integrated PSU mount for Project G5. With all the required parts at hand, it was time to take apart the insides of the Power Mac G5. All the plastic and metal internal structural components had to go.

This left a vast amount of space to work with, though it did mean I lost most anchor points for fans in the front section of the chassis. Leaving the shelf would allow for a bracket to be purchased from The Laster Hive, but I thought I could make a custom fan bracket further down the line. With the chosen CPU cooler and rear case fan, I'll already have three 120mm blowers pulling air through the Power Mac G5. Add in the GPU with its tri-fan cooling and the PSU and I should have ample airflow to keep things reasonably cool.

Unfortunately, the metal bar for the side panel latch snapped, likely due to the nuts securing it not being torqued enough and allowing it to bend. Some super glue addressed this and the mechanism works like new. Any unwanted hardware was recycled at the local household waste center, which happened to be just about every piece of metal and plastic from inside the G5.

Building a PC inside a Power Mac G5

It's easier than it looks

The Power Mac G5 has been used for many PC builds but I still thought I would encounter some hitch. Alas, it was time to get cracking ... or rather "dremeling." After marking out the areas I needed to cut from the rear of the Power Mac G5, the angle grinder made quick work of the perforated aluminum panel. Once enough of the panel had been removed, the new backplate could be placed atop the G5 and secured into place with a handful of screws, washers, and nuts.

With the rear of the Project G5 now taking shape and resembling the back side of a PC, it was time to focus on the motherboard tray or lack thereof. A metal ATX motherboard tray with preinstalled acrylic brackets is included with the conversion kit from The Laser Hive for mounting atop existing points inside the Power Mac G5 case. Before this was possible, the existing standoffs had to be removed. Thankfully, these can be knocked out of their housing with a light knock of a hammer. I would also remove the rest throughout the chassis as they will not be needed for the PC build.

The tray can then be attached to the inside of the Power Mac G5 and now we're cooking. It wasn't quite time for mounting hardware, including the motherboard, as more dremel work was required. The front I/O is incompatible with an ATX motherboard and thus The Laser Hive provides a pre-assembled replacement package with a sleek aluminum bracket and illuminated power button. There's also an array of USB-A 3.0 ports and some audio jacks for good measure. Again, marking around the template and cutting out the metal took some time. It's always best to remove a little and work from there.

With the front I/O upgraded to a PC standard with far better connectivity, it was finally time to install everything. Starting with the power supply, which hangs from the rear panel at the top of the Power Mac G5. At first, I was concerned with a slight flex due to the weight of the be quiet! Dark Power 13. It's a beefy PSU and sagged slightly, which wasn't a structural issue but I was considering the possibility of the metal case contacting the motherboard. I don't wish the PSU to rest on the side of the PCB so it was swapped out for one slightly less capable yet standard ATX size and weight.

The motherboard is installed inverted with the CPU cooler at the bottom of the Power Mac G5 and the PCI slots up near the power supply. It takes getting used to at first, but everything fits perfectly, including the large MSI RTX 4070 GPU. One drawback with the Power Mac G5 that I'll have to look to solve is cable routing. There isn't any, which means it's a spaghetti junction inside Project G5. Some cable ties help but it's not a permanent fix I'm content with and so this will have to be revisited.

Gaming on a Power Mac G5 PC is impressive

Cool, quiet, and unique

Booting up the system, I'm greeted by the glorious Ubuntu 24.04 login screen. Dual-booting with Windows allows me to enjoy the best of both worlds ... now natively on a Mac. Cooling is surprisingly effective with just three 120mm fans and a GPU spinning when under load. The XPG PSU doesn't move an inch, which is to be expected due to the massive power capacity. Running X4: Foundations, a CPU-intensive game, saw temperatures of the AMD Ryzen 9 7900 jump up to 68C, which is pretty good for a 12-core CPU, even if not all of them are in use.

The next step will be to improve airflow inside the case, not because it needs doing, but I'd like to provide a helping hand to drive in cool air through the front as I suspect some of the air used to cool the CPU and GPU is coming from the rear, which is where I'm exhausting the heat. This should reduce temperatures slightly without causing much more noise. A front-facing dust filter will be required, however. I was never a fan of the front grill not having anything to keep particles out and this will need addressing. A simple magnetic filter that can attach to the inside of the front grill will suffice.

After 20 years, I was finally able to own a classic Power Mac G5 / Mac Pro ... sort of.