Some custom PCs start with a performance target. Others start with an aesthetic. For this custom water-cooled PC, the customer wanted both.
The brief was clear: exceptional cooling, low noise and a build that looked as carefully engineered as it performed. With an AMD Ryzen 9 9950X3D2 and an INNO3D GeForce RTX 5090 X3 OC 32GB at its core, cooling could not be an afterthought. The entire system was designed around a full custom liquid-cooling loop, with the CPU and GPU under water and every visible part considered as part of the finished design.
This is the result.
Built Around the Customer
Performance was only one part of the brief. The customer cared heavily about aesthetics and wanted something clean, technical and refined rather than a PC filled with lighting for the sake of it. At the same time, they wanted strong thermal performance and low operating noise.
Those requirements shaped the entire build, from the HAVN HS 420 chassis and clear Alphacool water blocks through to the metal hard tubing, nickel fittings and clear coolant.
Nothing needed to compete for attention. The cooling loop itself became the centrepiece.
The HAVN HS 420
The HAVN HS 420 VGPU was an ideal foundation for this build. Its panoramic glass places the hardware and custom loop on display, while its internal layout provides substantial room for large radiators and complex water-cooling hardware.
HAVN designed the HS 420 platform around high airflow and extensive radiator support, including up to 420mm radiators at the top and side.
That space allowed us to build the loop around three 360mm radiators without making the finished system feel crowded.
The result is a case that still has breathing room, despite containing an RTX 5090, a large reservoir and pump assembly, three radiators and a full hard-tube loop.
Cooling an RTX 5090 and Ryzen 9 9950X3D2
This is serious hardware to cool.
The Ryzen 9 9950X3D2 is a 16-core, 32-thread processor with a 200W default TDP, and AMD recommends liquid cooling for optimal performance.
Alongside it sits the INNO3D GeForce RTX 5090 X3 OC 32GB. NVIDIA rates the RTX 5090 platform at up to 600W Total Graphics Power, so managing heat from the graphics card was every bit as important as cooling the processor.
Rather than relying on separate air and AIO cooling systems, we brought the CPU and GPU into one purpose-built custom loop.
An Alphacool Core 1 LT Aurora Acrylic CPU block handles the processor, while the RTX 5090 uses an Alphacool Core full-cover GPU water block with backplate.
The clear acrylic blocks also suit the design perfectly. Instead of hiding the cooling hardware, they put the coolant channels and internal machining on display.
Triple 360mm Radiator Cooling
A custom loop is only as useful as its ability to get heat out of the coolant.
For this system we used three 360mm radiators:
- 2x Alphacool NexXxoS ST30 360mm Full Copper Radiators
- 1x Alphacool NexXxoS Monsta 360mm Radiator
The ST30 uses copper cooling channels and fins within a 30mm-thick radiator body, while the Monsta takes things considerably further with its much thicker design.
Using three large radiators gives the loop substantial cooling capacity across the CPU and GPU. It also supports one of the customer's other major requirements: lower noise.
Rather than depending on aggressive fan speeds to control temperatures, the additional radiator surface area allows the cooling system to move heat efficiently at lower fan speeds during many workloads.
The Monsta radiator adds even more cooling capacity to the loop, giving us additional thermal headroom while still allowing the system to be tuned around quieter fan operation.
We are careful about calling any high-performance PC "silent", especially one containing an RTX 5090. This system was instead designed to keep unnecessary fan and pump noise to a minimum while still giving the hardware the cooling capacity it deserves.
The Loop as Part of the Design
The hard-tube loop is where the build truly comes together.
We used Bitspower 14mm brass hard tubing rather than conventional clear acrylic tubing. The straight runs and 90-degree sections create the strong horizontal and vertical lines you see throughout the system.
The tubing is paired with EK-Quantum Torque nickel fittings, rotary adapters, offsets and extenders. These allow the routing to remain deliberate rather than forcing awkward tube angles simply to connect one component to another.
At the right-hand side of the system sits the Alphacool Core Flat Reservoir 240, paired with its VPP Apex pump. The flat reservoir becomes a major visual feature while keeping the pump integrated neatly into the loop.
Clear Go Chiller Astro coolant finishes it off without hiding the internal details of the blocks or reservoir.
Under the lighting, the combination of black hardware, clear acrylic, nickel fittings and metal tubing gives the PC an almost industrial appearance.
Lighting as an Accent
RGB lighting was used to support the design, not dominate it.
Fractal Design Momentum 12 RGB PWM fans provide radiator and case airflow. Their lighting picks out the edges of the cooling hardware and illuminates the coolant path, while PWM speed control provides the range needed to tune the balance between temperatures and noise.
For the photographed configuration, cool white lighting was the natural choice. It complements the nickel and transparent water-cooling components and draws attention to the loop without overwhelming the rest of the build.
Flagship Hardware Underneath
Behind the water cooling is an equally serious platform.
The AMD Ryzen 9 9950X3D2 sits on an ASUS ROG Crosshair X870E Extreme, giving the system a high-end AM5 foundation for the processor and the rest of the hardware.
Graphics are handled by the INNO3D GeForce RTX 5090 X3 OC 32GB, stripped of its original air cooler and fitted with the Alphacool full-cover water block.
Power comes from an InWin P130II 1300W Fully Modular 80 Plus Platinum ATX 3.1 power supply, giving the system the capacity required for this level of CPU and GPU hardware.
Every major component was selected with the same principle: nothing should feel out of place in a build at this level.
The Finished Build
What makes this PC special isn't simply the RTX 5090 or the amount of water-cooling hardware inside it.
It is how everything works together.
The customer wanted a machine where aesthetics, cooling and acoustics received the same level of attention as performance. That meant spending considerably more time planning tube runs, fitting positions, radiator placement, pump location, fan control and component alignment than you would on a conventional build.
The finished PC still looks clean because much of that complexity has been hidden.
You see straight lines, polished fittings, clear water blocks and carefully positioned hardware.
Behind that is a full custom loop with three 360mm radiators, built to handle some of the highest-end desktop hardware available while keeping temperatures and noise under control.
That's exactly what a bespoke Computer Lounge build should be.
Want a Custom Water-Cooled PC Built Around You?
A custom loop gives us far more freedom than a standard PC build, but it also requires considerably more planning.
Whether you already have a case, colour scheme, cooling target or hardware combination in mind or simply want help developing the right concept, our team can design a system around what matters to you.
Talk to Computer Lounge about a bespoke custom water-cooled PC.
