Inspiration for my build comes from the legendary Petricor S4Max build. My goal was to get as close as possible, at least in terms of gaming performance, in the smaller S4M-C (which I failed to do - but more on that later), with off the shelf parts, fully internal PSU and water loop, and minimal permanent mods and fire hazards. I had already been running an air cooled S4Mini + ITX board + 9800X3D + cooler swapped 4080 Super build that proved to be too much for the electrical setup.
While nothing failed catastrophically, the PSU ran so hot that the connectors at the PSU side melted. Luckily, I noticed it during a routine inspection and ordered a new 500W HDPlex PSU before going back to the drawing board.
I acknowledge that my new build is not practical nor will it make much sense in terms of actual portability but it was really exciting to put together. Long story short this was a case of having tunnel vision to make the build work, and never stopping to think if I should.
PARTS LIST
Case: NFC Skyreach 4 Mini
This case has fascinated me since I first saw it over 5 years ago OT’s channel. It is somewhat portable and for me the perfect balance of size and performance and introduces the challenge of hardware compromise. Historically S4M builds were constrained to 330W/400W and 60/70 series Nvidia GPUs. The release of the all-in-one 500W HDPlex GaN opened the door for more powerful hardware.
CPU: 9800X3D
There really is no other choice for an all out gaming build. This CPU was in my previous build and has been optimized with a stable per core voltage offset configuration that averages around -30. While not officially supported, all modern AM5 CPUs with an iGPU will work in the ASRock X600. Unfortunately and somewhat fortunately, the motherboard has a hard CPU power limit of around 115W, but the 9800X3D rarely consumes more than that during regular gaming loads.
The 7800X3D would realistically be a better fit for the build due to the power limits of this motherboard and the inhererant power limit of the CPU
CPU Water Block: EK-Pro CPU WB AM5 Rack Ni + Inox
1 of few possible blocks that work in this build. The other is the EK annihilator which is likely unobtainable. Picked this one up on Ebay a while back and it works great. I was initially concerned with mixing and matching the inlet/outlet ports on opposite sides of the block, which is contrary to the manual's instructions, but it seems to work perfectly fine.
Motherboard: ASRock X600 USB4 (w/ 12v mod)
This is the smallest readily available AM5 motherboard that supports the 9800X3D. Unfortunately, this motherboard runs at 19v which creates a PSU issue. SO you either need to run dual PSUs, run a voltage converter, or mod the motherboard to accept 12v. Luckily the board is able to accept 12v, something the X300 was able to do natively, with a small resistor mod that is detailed further here. A key feature of this board is also the Gen 5 m.2 slot, effectively providing Gen 3 x 16 bandwidth for the GPU. This is enough to not lose any noticeable performance in modern GPUs.
GPU: PNY GeForce RTX™ 5080 OC
Any reference PCB RTX 5080 will work. The PNY's PCB is reference-ish and is not officially supported but still works with the alphacool ES block. For a drop-in warrantied version, Inno3D sells a 5080 with this block pre-installed (Inno3D RTX 5080 iCHILL FROSTBITE PRO). But it is pricey and you don’t get an air cooler for resale purposes.
GPU Water Block: Alphacool ES RTX 5080 Reference 1-Slot
The only readily available single slot 5080 block that works in the build. Crucially the face of the block is in-set from the IO area of the GPU allowing the block to sit flush with the outside face of the body of the case. This saves 1-2mm, without which I don’t think the build would work.
GPU Riser: ADT-Link F43SP Gen 5.0 x4 NVMe to PCI-E x16
I am sure there are other Gen 5 risers that will work. I stumbled across this one and it turned out great. Orientation, size, and cable length work great for my build. I did have to bend it back on itself to make the turns work.
RAM: Kingston 32GB PC5-5600 CL46 SODIMM
The 9800X3D doesnt need anything special here, just happened to have them in my laptop. Kingston sells faster RAM if you wanted to maximize performance. As far as I know the Kingston 6400 cl38 is the fastest kit.
PSU: HDPlex GaN 500W (all custom-ish cables)
A key piece of hardware that makes this build possible. Given the previous failure, the goal was to provide as much cooling as possible. I achieved this via 3 methods. Not expecting any issues this time around but fingers crossed.
1. There is a thermal pad that connects the PSU directly to the 140mm radiator
2. There are thermal pads connecting the back of the PSU to the front heatsink bezel
3. I have modded the top PSU cover to accept a 40mm Noctua fan. Not shown in the pictures above - but will be shown in the build log.
Cables are semi-custom and I am now using all corsair type 4 OEM connectors at the PSU. In my previous air cooled build I used a mix of the original HDPlex connectors and aftermarket connectors from dreambigbyray – both of which seem less robust than the corsair parts. The 12vhwpr cable is also a corsair OEM type 4 part that has been repinned to plug into the HDPlex's EPS and PCIe outputs.
The CPU is powered by the motherboard via the stock DC jack. I created the cable using some adapter jacks available from amazon. Unfortunately, the first set began to melt and fused together and ultimately broke when I pulled them apart. Fortunately, nothing else is damaged and I simply removed the adapters and replaced them. If it happens again, the plan is to cannibalize the stock power cable and crimp the cables directly to the PSU.
The riser originally came with a sata adapter cable which I didn’t really have space for. For my purposes I actually used some old J-Hack M2426 cables that can be repurposed. Luckily, for whatever reason, this 5080 only pulls ~3W or so from the PCIe slot so I don’t think these cables are getting overloaded. One issue that arises when using a riser that is externally powered with a motherboard that does not support the PSON function is that the PSU needs to be permanently jumped on, which results in the riser always supplying 12v to the GPU. My RTX 5080 pulls 30-40w even when the system is shut off – this can quickly lead to overheating and failure if left without cooling. This introduces the need for an external switch. I grabbed this switch from amazon. This does create a two step process for powering on and powering off the PC, but it is a small price to pay.
Storage: SN750 1TB
Nothing special but ideally the drive consumes little power and does not get hot as it is completely sandwiched between the motherboard and GPU with no room for a heatsink. A Gen 3 drive achieves this.
Pump: Alphacool DC-LT 2
There are a few DC-LT models. This one was readily available and works great. I have heard that these pump tend to give out so I’ve purchased a spare.
Pump Top: Alphacool DC-LT Acryl Top
Perfect sized pump housing for my build. It also functions as a pseudo reservoir given its multiple ports and transparent nature. I did have it professionally cut down 2mm on one of the sides for it to sit square inside the case but it isn't strictly necessary. One benefit of its orientation is that I can top up the loop while upright and can visibly see how much coolant is needed.
Coolant: Koolance 702
Heard some good feedback on the longevity of this coolant. So far so good.
Rad: CORSAIR XR5 140mm
This is the smallest 140mm radiator that I could find locally. Grabbed it for $20. I’m sure there are better options out there. But this seems to be working fine for now. Any similarly sized 140mm rad should work fine
Radiator Fan: Noctua NF-A14x25r G2 PWM
These fans have a smaller rounder frame than your typical 140mm fan but with the same sized fins. This allows for much improved tube routing and cable management with no impact to airflow. One issue is that because it uses 120mm screw mounts you need to find an adapter to secure the fan to 140mm rad. 3D print files are here.
Case Fans: 7x NF-A4x10 PWM
NFC Dru made me some custom carbon fiber S4M brackets with built in support for 40mm fans. The 7th fan is installed at the rear of the PSU and keeps the PSU cool enough to touch even under load. I would guess the PSU gets to roughly 42-45C during sustained gaming loads ~330w or so.
All of the 40mm fans are powered from the GPU.
Fittings: Legris Pneumatics 8mm OD
Legris was readily available via Grainger, the local Canadian vendor. I originally bought cheaper fittings from aliexpress but they were not great at being air tight let alone water tight. Just go with Legris/Festo and you should be good.
There are loads of other custom bits here and there that I will detail out in the build log. I would say the build is 99% done at this point.
I am able to run prime 95 and furmark simultaneously without crashes. Hits around ~550W at the wall. The GPU can pull 360W and the CPU can pull 115W as reported in HWINFO. During a typical hour long gaming session the GPU averages 65C and the CPU around 75C with the fans at 70%.
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