Devyn Johnston Assembles One of the Thinnest RTX 5090 Gaming PCs Ever Seen

Devyn Johnston has spent years chasing smaller and smaller gaming machines, and this latest effort pushes that habit into territory that feels almost stubborn. Inside the ZCOOI Mugitya FE9, an RTX 5090 Founders Edition sits in a chassis that measures only 56 mm thick across the top and 79 mm at the base, all while still packing a full desktop processor and a 1000-watt power supply. The case arrives as a set of thick CNC-machined aluminum pieces, each finished in black or silver anodizing with a few gray-gold accents on the nameplate and front panel, and the whole collection ships inside its own aluminum carrying case.

Assembly begins by removing the back panel, front cover, and bottom portion, which are all held together with run-of-the-mill screws, so you can just put in the mini-ITX motherboard. Johnston chose an ASUS ROG Strix X870I for this build, which included Wi-Fi 7, a 2.5 gigabit Ethernet port, and a couple of USB 4 ports. He then topped it off with a 64GB of DDR5-6000 RAM, split evenly between the two memory slots, and paired a 2TB Samsung 990 Pro with a second 2TB 980 Pro for a total storage space of 4TB. The power supply is the Corsair SF1000, which is stealthily installed on the bottom panel, and every single cable has been cut to a custom length to ensure that nothing takes up room inside the box.

A Thermalright AXP90-X47 low-profile all copper unit provides cooling and stands only 47 mm tall, comfortably fitting within the 49mm clearance on AMD boards. Johnston liked the orange fan so much that he replaced it with a black Noctua model, which allows you to see the blur of the fan spinning from the side panel without detracting from the overall beauty of the build. The graphics card is attached using a solid PCI-E riser rather than a fragile cable, and to get it to fit properly, Johnston removed the original bracket and bolted it directly to the chassis, allowing the coolers to rest behind matching holes in the panels.

One minor detail turned out to be the standout. The power button is based on a conventional keyboard key, and the case has four removable keycaps in black, white, transparent, and semi-transparent finishes, allowing you to customize it to suit your mood. Once everything is in place, the chassis weighs 6.5 kg and is supported by one of two available foot types, a narrow bar or a broader set for added stability. Magnets hold the side panels and coverings in place, allowing you to open the item with little more than the included aluminum screwdriver.

He put the finished machine through its paces, running The Witcher 3 Remastered at a smooth 120 frames per second on extreme with ray tracing and DLSS Quality turned on. The graphics card maintained a consistent 230-240 watts while staying cool at 54 °C, but the 7800X3D drew 53 to 60 watts and peaked at 70°C. Resident Evil Requiem drove the GPU to around 500 watts and 71-74 °C, but it still managed to maintain frame rates around 130. Cyberpunk at a resolution of 5120 by 2160 with strong ray tracing pushed the GPU to roughly 500 watts and 71-72 °C in the middle of the action, while the CPU reached nearly 80 °C under load. Downsizing to 1440p resulted in the GPU maintaining a very respectable 430-450 watts and 67 °C. The only issue occurred during the initial shader compilation, when the CPU soared beyond 95 °C, but as the game stabilized, the temperature remained within the range of what a low-profile cooler can tolerate.

When the system is up and operating, noise levels average around 43 decibels, with an occasional electrical hum from the power source that refuses to go away completely. The design does not allow for additional case fans to be installed, allowing the graphics card’s own cooler and copper heatsink to handle the work. He also has to consider that this case was designed specifically to house the Founders Edition 5090 (as well as the 5080 FE or PRO 6000), so swapping out the graphics card later for something new would necessitate tearing everything down and rebuilding, or ditching the case entirely. Johnston appears to consider this setup as a beautiful piece of technology to admire rather than a tool to be used on a daily basis. Yes, it achieves high frame rates while taking up less area than a typical tower.

A complete system would cost roughly $465 for just the case, before you add in all of the additional components, and the issue is, every component must fit perfectly or the entire thing will not close. When everything is fully put together and the last panel is clicked into place, you have a slab of aluminum that houses a full 5090 and an 8 core processor, all held together by magnetic panels and requiring only one keyboard key to boot up the system.