Log Walrus U5: a 4.8L fully water-cooled build with a 240mm radiator and RTX 4080

[morj]

Hi, folks!

One of the gripes about my previous personal rig was the use of external radiator.

If my calculations are correct, I can fit full-blown desktop hardware (including a DDC pump, 2x12025 fans, and a 240mm radiator) in well under 5L.

Provisional specs:

• Ryzen 9 7950X3D
• GeForce RTX 4080 (based on Gainward 4080 Phoenix GS)
• Dual Noctua NF-A12x25 fans
• Alphacool NexXxoS HPE-20 Full Copper 240mm Radiator
• EK DDC pump
• Alphacool Eisdecke DDC pump top
• Origial EK-Annihilator for 1U (CPU waterblock)
• 800W PSU (modded PWS-804P-1R)

I'm not going for a PPL record, but I hope it will be a pretty well-rounded build, cool and quiet, while hosting an RTX 4080.

Provisional dimensions: 272 * 178 * 100

 

[morj]

As you might have noticed, the waterblock on the GPU looks unusual.

This is because I faced a following problem: there is no way neither the block terminal nor the power connector would fit the layout pictured above.

The first problem is addressed by a custom water block cover I had to design:

The thread pictures a copper version, but for now I'm using a cheaper one made of POM just to verify it works as intended:

The power connector issue is solved by using the pads conveniently located next to the water block on the GPU PCB:

This was very hard to solder due to PCB absorbing heat, so I had to seek help from a professional electronics wizard

Those bullets are of course compatible with my tried and true PWS-804P-1R power supply setup:

I was worried that the GPU might have been fried by such a surgery, but it seems to be doing fine!

 

[morj]

I'm still working on the case (and waiting for the Noctua fans), but I could make a provisional component fitment test with an old Intel motherboard.

Also bought a copper DDC heatsink from IceManCooler. Wanted to go with Modultra "Slammer" heatsink, but VAT + Shipping from USA would have made it exactly 2 times the price (100€ instead of 50€).

IceManCooler is still a bit more expensive than the one made by EK, but being 68x68mm it couldn't fit my layout (unlike IceManCooler that was normal 62x62mm).

Test fit with some Arctic fans (not mounted).

Test fit of the radiator (I like this picture a lot).

Also did some provisional loop with pneumatic fittings just to make sure there are no surprises.

The pipes should go alongside the CPU waterblock, but it's not possible with Intel mount due to it being square. On AM4/AM5 there will be more space alongside the waterblock.

 

[morj]

Also I started wondering, which layout is better:

A (or maybe flip the fans as intake):

Or B:

 

[Dr Diver]

Hi,
Currently working on the same kind of layout myself (only made plans), same hardware but less watt consuming CPU, unmodded GPU block and HDPLEX 500.
I'd always go for B layout : maybe a little less noise and surely a lot more easy to clean dust on radiator.
Cheers and thx for the tip on the 4070 GPU block working on some 4080 in one of you older posts.

 

[morj]

Hi,
Currently working on the same kind of layout myself (only made plans), same hardware but less watt consuming CPU, unmodded GPU block and HDPLEX 500.
I'd always go for B layout : maybe a little less noise and surely a lot more easy to clean dust on radiator.
Cheers and thx for the tip on the 4070 GPU block working on some 4080 in one of you older posts.

Yeah, but it's better to use the 4080 Panther (and not the Phoenix):

(image taken from this reddit post)

As you can see, the Phoenix (below) has one additional mosfet, which will not be covered by the 4070Ti waterblock. So better have a PCB like on Panther 4080 Super without this mosfet (like pictured above).

 

[morj]

Also in case I run into some fan clearance issues, I have extra 3mm to spare using the eedev's approach with making a custom 22mm fan frame (except here I'll make a 2-for-1 frame to add some rigidity and radiator support).

(At the fan hubs the thickness is more like 23mm, but that's OK since I'm mostly concerned about the frame interfering with the motherboard I/O shroud)

 

[Dr Diver]

Thx for the tip on the Panther, I have not bought the hardware yet so it's a precious one !

You didn't mention it, but if you want to use a temp sensor to control the fans, I've found this solution, which eliminates the need for a 12v power cable, is smaller than a Quadro, cheaper and can be used to control RGB as well :
Adafruit Trinket M0
I seem to remember you know a bit about coding in Python, so it shouldn't be too hard for you to find a solution.
Otherwise there's a guy who already made a plug in in order to use the signal as a temp sensor in Fan Control.
A video from the code writer, everything is explained more clearly than I could.

On another subject this guy makes bespoke GPU blocks and/or covers.
Never tried his products, so I can't say anything about his work but I've read good things about him on a french forum.
He's french, I'm too, I could help with language barrier if any ;-)

And last to gain 3 mm in thickness : a 17mm radiator, 2 mm longer than the Alphacool though. There are a few amateur reviews here and there but hard to judge perf wise.

I forgot in my first post : awesome work as always !

 

[morj]

cheaper and can be used to control RGB as well :
Adafruit Trinket M0
I seem to remember you know a bit about coding in Python, so it shouldn't be too hard for you to find a solution.
Otherwise there's a guy who already made a plug in in order to use the signal as a temp sensor in Fan Control.
A video from the code writer, everything is explained more clearly than I could.

Thanks! I'm a software engineer by trade, so it won't be a problem for me. I already have the Quadro from my previous builds, but will keep your solution in mind in case I run out of space. Thanks again for the tip!

 

[morj]

And last to gain 3 mm in thickness : a 17mm radiator, 2 mm longer than the Alphacool though. There are a few amateur reviews here and there but hard to judge perf wise.

I think there is a common knowledge that such tube radiators are much worse in performance. For example, aqua computer airplex were also based on this design and they seemed to perform worse than regular radiators of equivalent dimensions.

 

[morj]

Thx for the tip on the Panther, I have not bought the hardware yet so it's a precious one !

BTW, it seems that the cause of the lack of this mosfet is not particularly the Panther model, but that fact that it's a 4080 Super. From what I read, the 4080S reference PCB just omits this component.

 

[msystems]

Quite excellent custom work as usual!

 

[morj]

Finally!

Got the hardware for the build, time to put it together!

Im using the slightly lower m.2 heatsink from Thermalright to reduce the height of the m.2 assembly compared to the original board (and also to match the AM5 secure frame).

On the rear there's an old system drive (the main one under the heatsink is PCI 4.0).

EK-Annihilator 1U with AM4 mounting bracket from EK-Supremacy Classic.

Now for the case/build itself.

I am still cautious about ordering metal side panels since I haven't worked out the small details of the layout. For example, the space I originally intended to use for the power button will be occupied by aquacomputer quadro. I will have to use a smaller power button and put it elsewhere.

The build has a couple of 3D-printed fasteners where I couldn't get away with using metal corner cubes.

This one is used for the motherboard corner (need to tie together the hole in the motherboard and 3 case panels).

This one is combined PSU/Quadro mount.

Quadro goes between the RAM and the PSU, so I had to snip RGBpx and aquabus connectors.

Riser goes under the motherboard. Unfortunately, there are some components slightly interfering with it, so I had to lap the riser with sandpaper.

Added some electrical tape just in case.

The GPU is mounted directly to one of the panels (doubling as a backplate, at least when I'll order metal side panels).

I used nylon locking nuts to avoid them getting loose (too much high power components around).

Rear panel mounted together with the C14 connector.

Riser goes in.

Some tape for the CPU EPS connector.

Motherboard in.

Pump mounted to the side panel (I found this inconvenient later on, but I don't have mounting holes in the front panel yet).

Drilled a crude drain/fill hole (initially this panel didn't have it).

Note how the pump houses a thermal probe to measure water temperature.

Checking PSU position.

Some initial cable management.

Spot where the Quadro is mounted.

Note that the PSU has now a removable mains cable.

Some more cable management.

Checking the loop.

The radiator swings out. When it's in, it's hard to take pictures (but you get the idea how hard the cable management is).

I will probably try to move as many cables as possible to the motherboard side (the one where the the 24pin is, between the 24pin and the Quadro).

The other side looks much better.

Testing the loop again (I had to change the radiator side fittings).

I found it impossible to fill the loop with everything assembled. Luckily, I can put everything into "service position" without disconnecting the tubes.

That's how the loop is being filled and bled for bubbles right now.

This will take a while....

The exciting part is that I can control everything (coolant temp, fans, but most importantly the pump speed) from my laptop.

Stay tuned!

 

[morj]

So it's been a week since this build has first POSTed and I must say it is a great success.

This is how it looked first.

I spent this week installing fresh software, tuning the CPU, RAM, fan curves. The cooling performs exceptionally well.

The only thing I haven't done yet is overclocking or undervolting the GPU. Hope to achieve better TimeSpy results later on. Current picture:

As for Cinebench r23, I'm pretty satisfied with what I get right now at -10 PBO all-core undervolt, 87°C temperature limit (slightly under Tjmax).

The most amazing thing about the cooling is that after running a 30 minute Cinebench test the water temperature is 29°C (with ambient temperature of 21°C). I've set the fans to full speed for the test, but still the delta is pretty awesome.

So current unofficial PPL is (35560 * 27668) / (4.8^1.5) / 100 ~= 935573. Not too shabby.

Unofficial because the panel design is not finalized and the outside volume is a bit bigger due to prototype plastic panels (that must be thicker than metal).

One might notice that the power button on the front panel is unoccupied.

This is why: my fan controller (Aquacomputer Quadro) and the related wiring (pump, fans, Quadro internal USB) took up too much space.

The Molex connector on the Quadro can be removed, but I like the modularity.

Anyway, there is a more straightforward solution: relocate the power button. This will be fixed in the next update.

 

[morj]

To fix the power button I had to print a new front panel.

Which acommodates a slimmer power button than a usual vandal switch.

(The button comes from LZmod)

I also like the vertical orientation, but it makes the cooling worse (left and right side panels are used as intake).

Also notice that the pump is now mounted to the front panel as well utilizing the two M4 mounting points the pump top is providing.

The front mounting should provide better pump cooling since the pump will be pressed agains the future metal front side panel (to which it has bigger contact surface than to the side panel).

I also printed a small cover for the PSU (to save plastic and time compared to a full top lid). Never mind the bulging, this is plastic being plactic.

This is how the setup looks right now:

 

[petricor]

Very very very cool project - I really like the layout... have been toying with a 5l/240mm/4090 layout for a more silent build compared to using a single 140mm with a high powered fan... are you happy with the acoustics?

 

[morj]

Very very very cool project - I really like the layout... have been toying with a 5l/240mm/4090 layout for a more silent build compared to using a single 140mm with a high powered fan... are you happy with the acoustics?

I'm wasn't fine-tuning for acoustics TBH. My goal was to confidently cool all the components, hence I have set the target water temperature to 40 degrees C, so my fans ramp up to almost 100% under full load. This doesn't concern me since I'm playing games at 1440@240Hz while wearing IEM headphones. The PC is very close to me on my desk and doesn't bother at all.

Having said that, I'm very pleased with the cooling performance. It definitely has headroom and if you are willing to set a higher water temperature target you might get away with lower fan speed and hence a more silent operation. When the load is gone the water temperature goes down really fast which in turn makes the fans silent.

Without headphones I can also hear a tiny amount of panel resonance (when the fans are running full blast), I think this can be addressed by finally using sturdier steel panels instead of plastic prototypes.

@petricor I've made a short video for you to give you an idea of how it sounds (when the fans are forced to run at 100%):

 

[petricor]

I'm wasn't fine-tuning for acoustics TBH. My goal was to confidently cool all the components, hence I have set the target water temperature to 40 degrees C, so my fans ramp up to almost 100% under full load. This doesn't concern me since I'm playing games at 1440@240Hz while wearing IEM headphones. The PC is very close to me on my desk and doesn't bother at all.

Having said that, I'm very pleased with the cooling performance. It definitely has headroom and if you are willing to set a higher water temperature target you might get away with lower fan speed and hence a more silent operation. When the load is gone the water temperature goes down really fast which in turn makes the fans silent.

Without headphones I can also hear a tiny amount of panel resonance (when the fans are running full blast), I think this can be addressed by finally using sturdier steel panels instead of plastic prototypes.

@petricor I've made a short video for you to give you an idea of how it sounds (when the fans are forced to run at 100%):

NIce... not bad.... not bad at all!

This is what I came up with testing the concept of a 240mm rad with a 4090- slightly different configuration as the GPU is a tad wider; it's 4.8l if you wrap it in tin foil, but by the time it would be clad with something that can remotely compete with the looks of my beloved S4 Mini (the reason I got into SFF has been disagreeing with the way most PCs look like, after all...), it is more like 5.0:

The idea is relying on machined front- and side panels to control the edge geometry, with sheet metal for the top, rear and bottom faces. May wait for the next gen of graphics hardware, though, as that case wouldn't come cheap to make...

...and listening to your video I realise that putting the fans below the rad is nicely activating it to shield some of the fan noise: Thermally it makes no difference, but acoustically it does!

 

[morj]

...and listening to your video I realise that putting the fans below the rad is nicely activating it to shield some of the fan noise: Thermally it makes no difference, but acoustically it does!

Wow! Great to see a sneak peak of your potential future project.

IMO your layout is better (even if larger than 4.8L) thanks to the founders edition cards (like the 4090 that you have) being thinner, plus you have an exceptionally thin intricate water block which in turn gives you more volume to work with and much better airflow for the radiator. The layout in your picture will have better water temperature delta than mine, I think, due to more direct air path. Mine is not bad though (one can feel the air being sucked in through the case sides left and right quite nicely). The upsides of my layout are: 1). a more powerful pump with its own passive heat sink can be used 2). it's actually 4.8L with 1mm panel thickness. The PPL scores tell that 4090 has more PPL uplift versus 4080 than 0.2L difference though.

Regarding fans and radiators: both water-cooled SFF builds with internal radiator that I have done had fans blowing out of the case through the radiator. I always thought that it's the optimal layout if the airflow is sufficient: there is no hot air trapped anywhere inside of the case. And, as you mentioned, there is a bonus in terms of acoustics.