Log Hardline Water Cooled 5.5L Build


Chassis Packer
Original poster
Jul 22, 2022

I've written the original build summary around seven months ago, but since it kept failing, I almost scrapped the idea, until I found the Bykski compression fittings, which saved this project and I barely managed to finalize it. The different iterations this build went through are described in the picture below. I slightly tweaked and edited my original summary, adding new benchmark results, but mostly left the original build process summary intact. Enjoy.

In the last couple of years, ever since I discovered the mini-ITX craze, I've been toying around with the idea of building the smallest SFF water cooled PC. I first started with the dual mini AIO mod in a K39 case, then made the original "No Space Wasted" build using the Alphacool Eisbaer LT in a custom loop with soft tubing. And recently I completed the A09 water cooled build. At that point I thought I was done, but deep down, I always wanted to try a mini-ITX full hardline loop and so this dream became a reality, although it proved to be quite an ordeal.

I will list out the specs first before going into the build process:
-Ryzen 5 5600
-Modultra LOBO Low Profile Water Block (Alphacool Liang DDC310 Pump)
-PNY NVIDIA GeForce RTX 3060 12GB XLR8
-Bykski N-GY3060XJ-X GPU Water Block
-Syscooling AS160 Aluminum Radiator
-Freezemod LSJ-ZNR Digital Flowmeter
-KLEVV BOLT X 16GB kit (8GB x2) 3600 MHz
-Crucial P1 1TB NVMe SSD
-MF 650F 1U Flex PSU
-D21 Case (old version)

I started with my old components from the original "No Space Wasted" build, only upgrading from 2060 to 3060. My first hurdle was trying to find a suitable water block+pump combo, since nothing that sold on the market fit in my case. This is when I stumbled upon the SFF.Network forum and discovered the existence of the Modultra LOBO. Not only did it fit perfectly with a few millimeters to spare, but it also has a neat feature of cooling the pump using the loop thanks to its full metal block design.

Since I used dual 80mm copper rads last time, I found them to be not that great for optimal water flow, so I decided to risk it and go with an aluminum 160mm rad, which was the only rad that could fit. Simply strapping 80mm fans in a conventional way couldn't be done due to space constraints, so I first created the GPU fan style prototype. It was functional but didn't look great, so I opted for a better solution instead.

I acquired smaller 70mm PWM 6000 RPM fans, cut small grooves into the corners and basically wedged it in between the fins and the fan mounting points on the rad, essentially creating a toolless fan installation. This also worked out great for airflow, since the fans were now almost fully contacting the fins, limiting air leakage. I realize that this way the fans could potentially deform or possibly melt if the rad gets hot enough, but I've been running multiple stress test hours on end and I've yet to see any damage. Hopefully that won't happen, since this machine will only be used for editing and gaming.

And so, I completely assembled the first iteration of the system, pressure tested and filled the loop. I previously used the Liquid Utopia from PrimoChill, but after running it in the previous soft tubing version of the build, it accumulated algae just after six months, despite no presence of mixed metals in the loop, so I decided to try PrimoChill's True clear fluid this time. That was a mistake...

This is what happened after running it for a few days. It gradually got worse, ultimately turning into this milky consistency and staining everything in the loop. Now, to be fair, PrimoChill strongly advises against using this liquid in a loop with mixed metals, but I hoped it would last longer than a week... Apparently, the reaction was almost immediate. Unfortunately, I had to completely disassemble the entire thing, deep clean all the components and this time I opted for the best liquid for mixed metals I know: Antifreeze. I bought a basic car antifreeze premixture and diluted it further, about 85% distilled water to 15% antifreeze.

I initially wanted to use PETG tubing for the runs, but ultimately decided to try copper ones. The rest is built using various types of fitting extensions. I really tried implementing as much of the tubing as I could, unfortunately there was not enough room and I was not trusting myself to make copper tubing bends. However, after the loop failed twice, I swapped the chrome plated copper tubes to pre-bent matte black copper tubes and switched all the fittings in the loop from standard Barrow triple o-ring hardline fittings to Bykski compression fittings with one large rubber gasket that tightly grips the tubing, insuring there's no slipping. I've tested both Alphacool and EKWB o-ring type compression fittings in a makeshift hardline test loop using both matte black and chrome plated copper tubes and both eventually slipped and failed, while the Bykski single rubber gasket never failed both in testing and in the final build.

Finally, I want to share some benchmarking data and temps.

Idle temps are relatively basic, the T_sensor temp is a probe I have embedded into the pump housing to monitor its temp. As you've seen, I have a digital flow rate which also shows the water temperature in the loop and the idle water temps hover at around 34/36c. CPU at 39/42c. GPU at 34/36c. Finally, the pump is at around 38c.

Stress testing the system has the GPU max out at around 73c and the CPU reaches 95c, while the water temperature hovers around 57c. I did undervolt both the GPU and CPU slightly and I think the little 160mm radiator is doing its best cooling 270 watts. This is an unrealistic use case though and the system runs a lot cooler and draws way less power while doing mundane tasks like editing or gaming. I've also included some 3DMark scores, for those who are curious.

Here is Resident Evil 4 Remake, running 1080p high/max settings. The CPU doesn't exceed 80c and the GPU stays at a nice 71c. The tiny 70mm fans obviously ramp up at this point, but aren't running at 100%, so theoretically I could lower the temps even more, but the fan noise would definitely start being an issue.

Last thing I did after completing the final revision of the build was replacing the acrylic side panels with custom mesh dust filters held by magnetic strips. I think it looks much nicer and actually helps the system stay much cooler.

In conclusion, this was a long and complicated journey, full of failures and struggles, but I did manage to finally finish another pointless crazy project of mine. Stay tuned for my next (arguably the craziest one yet) build, which involves a certain SFF GPU that I finally got my hands on and I can't wait to get started on that project!