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Liquid cooling for EPYC - need advice

UPDATE APRIL 21:
As Noctua is coming out with a mounting bracket solution to adapt their 3647 air coolers to EPYC, I will likely be going with that solution instead. Thank you all for your input and advice, I learned a lot!


I’m planning an Epyc workstation build in the Dune Pro case, based on the AsRockRack ROMED8-2T motherboard (coming out next month).

I was originally going for a Noctua heatsink and fan combo, but realized that their TR4/SP3 models presume the CPU is oriented vertically like on TRX40 boards; EPYC server boards have the CPU and RAM slots laid out horizontally. (Probably makes sense in a 1U rack where you’d have a bank of high speed blower fans pushing air from front to back.)

So I’m turning to a liquid cooling solution. Similarly to LinusTechTips “Fake Mac Pro” build, I’m now looking at mounting an AIO unit as the front intake fans, vented to the back by two 80mm Be Quiet fans.

Yes, this means the CPU heat will be blown back through the case, but most sources seem to indicate this won’t cause problems. EPYC tops out at 180-220w TDP - should I even worry?

I’m looking at the Alphacool Nexxxos 360 kit that has three Be Quiet Pure Wings fans, but I’ve been looking at EKWB stuff as well. Silence is my main concern.

Any thoughts / recommendations? Should I go for the kit, or is there a mix-and-match solution of radiator / fans / waterblock that will work better? (Can you mix brands?)

I might have room for a reservoir but would prefer not to use one.

Thanks!

Parts are pretty much interchangeable, since it’s just water. The standard threading is G1/4 and you will find that on pretty much all standardized parts and fittings. You can choose what size of tubing you want, any of the common sizes will be fine, just match the actual tube to the fittings.

From my experience, testing, and reading the testing of others my favorite parts in each category are:

Rads: Considering you want low noise, you would want rads that perform nicely at low speed, like 750rpm-1300rpm.
Thin: Avoid if you can, otherwise, the Alphacool ST30 performs soso. The Hardwarelabs GTS performs great but is water flow restrictive as fuck.
Medium: Alphacool XT45 ties with EK PE for performance, Alphacool has more ports for routing flexibility.
Thick: Hardwarelabs SR-2 does the best at the lowest speeds, and even remains quite good at higher speeds, but is overtaken by the EK XE by the 1300 mark.

Fans: Previously Gentle Typhoon or EK Vardar but if you have the cash the new https://noctua.at/en/nf-a12x25-pwm are excellent. All very close though. You will notice these all have a similar sickle shaped blade and that tends to be the magic. It’s a much superior design for pushing air through rads and staying quiet doing it. A cheaper option is the Arctic P12 fans.

Blocks: This is chip size / available mounting or GPU specific. I usually turn to the data. For Threadripper / HEDT sized chips as of the latest I can find, either the Heatkiller IV Thredripper, or XSPC Raystorm Neo Threadripper. The EK options are… ok. Aquacomputer and Alphacool are not very good.

Pump: Any D5 based option should be alright. I personally run the EK dual top PWM D5, but dual pumps is very overkill for a lot of things, despite the redundancy bringing with it a nice sense of security. D5s are known to be quiet and reliable. You might also see the DDC, which I have found the be quite reliable… at killing itself due to overheat at about the one year mark. Even the newest revision, and the older ones were worse, infamously so. That said I never gave any of mine (and I had a few) any airflow, something that the D5 does not need as it has a metal impeller casing and sinks its own heat into the water. There are other pumps, but except for one particular Koolance and one Swiftech, none of them are “high performance” pumps like the D5 or DDC, which would allow for more expansion of the loop later on. Other than that, some kind of speed control, whether it be just a switch (like on a Vario model) or PWM is a nice feature for filling.

Pumps Continued / Reservoirs: A very popular way to mount the pump now a days is directly onto the reservoir with a custom “top”. Which, speaking of, you mentioned not wanting. While it can be possible to run without one in a a few specific scenarios, you need at least some amount of standing water supply sitting above the pump in respects to gravity, as these impeller pumps need to be gravity fed, especially during filling. You do not want them to run dry for any notable amount of time. The old way was using a T line, but it is noticeably harder to fill. The other big benefit of having a reservoir is that they are nearly key in getting your loop to fully bleed its air bubbles easily. If you wanted to have your pump separate, something very small like a Swiftech Micro Res is an old classic.

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Is your air cooler issue, but yeah you can do a custom loop or AIO. Normally wouldnt be an issue since exhausting up is ok but since its a solid panel yeah. Cool issues tho and didnt really have any luck with coolers that makes sense for your use case that would be large and quiet.

Would not recommend this you can get pump/rez combos. Its not to say its doable but filling / removing air from loop becomes much more difficult. I honestly would just for for an AIO. Enermax has full cover blocks in AIO form. You would trade better cooling performance for possible loss of pcie lane since pump / rez would need mounting area.

Never had that issue but they are way louder then D5 if you have to run at a higher

@Pawmaniac good coverage on the topic tho not much to argue about with your comments.

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WOW. Thank you very much for the in-depth answer! I will look into these more closely.

Here’s a bit more context if it helps:

  • Running a Radeon Pro WX2100, the basic card that can support 2 4k monitors. I don’t need anything more than that, so GPU cooling is not going to be an issue.
  • One slot will be taken up by a quad NVME m.2 carrier, and over time I will populate 1-4 slots with audio DSP cards (the chips don’t run very hot; there are 8 per card - the point is to take pressure off the CPU for running VSTs and effects). Might use another slot for USB 3.2 type C ports if I need them.

So basically I don’t foresee having to expand the cooling loop.

The Dune case has room at front for standard fans, but I think if a thick watercooling radiator is installed I might have to remove the front drive cages (they are optional), but there is a secondary 3.5" drive cage that mounts near the PSU, so there could be space for a reservoir/pump on the floor of the case. (There’s no top venting or mounting points.)

So - regarding the radiator and fan choices, thicker is better = more surface area? Does copper or aluminum make a difference? I was looking at whatever replaced the EK Phoenix, I rather liked the design of the Nexxxos as it has some features to prevent accidentally damaging the radiator pipes/vanes with screw mounts but EK has a good design too.

Noctua was what I was going to go with for the air cooler in my original plan, so maybe going all-Noctua instead of all-BeQuiet! is a better plan.

A D5 pump - Yeah, I think I just need a single, so is there a brand you recommend? When you say speed control, is that a separate device or a feature of the pump?

Thanks :slight_smile:

Yeah, it’s the Mac Pro clone design. (The one thing it adds is bottom intake vents for the PSU, the real Mac doesn’t have that). It is all made of very solid aluminum, so I am wondering if the case itself will just act like a big heatsink?

I would prefer the simplicity of an AIO, sure, but I’d also like reliability. I think I might mix-and-match as Pawmaniac suggests, but keep it as simple and idiot-proof (read: me) as possible.

Yes, thicker is generally better for having more surface area. Also, the “thin” (~30mm) class ones are also usually higher restriction, both for airflow and water flow. The Hardwarelabs GTS does alright for airflow, hence it doing decent at low fan RPM, but is pretty crap at water flow. Though, in a small loop that shouldn’t be an issue.

You won’t generally see aluminum in custom loop parts, some AIOs use it but they are designed down to a price and have the necessary mitigations against corrosion. See, while copper does have better thermal conductivity - hence why blocks are almost always made from it - it’s also a bit more expensive. Also, copper and aluminum are rather galvanic corrosive to each other when in a high ion exchange environment like water, so while AIOs can design around it, it’s been understood to be a lot simpler to avoid using aluminum in our loops. Don’t even have to think about it really.

Any of those sickle blade shaped fans are quite good. I actually used to be a bit anti-Noctua until they came out with their own version of it. The beQuiet fans are alright as case fans, never really though of them as radiator fans though.

Most of the time, whatever D5 that comes bundled with whatever reservoir you like the most. Swiftech makes a pretty small package, the X50 I think.
Otherwise, most stand alone D5s are pretty similar, whether you buy them from any of the big names in PC water-cooling. The speed control is just down to the variant, so a Vario has a switch on it or PWM can take a PWM signal. The EK ones have some nice built in vibration mounting and a good top, but they tend to be more expensive.

A fun aside, since I didn’t connect that the Dune Pro was that Mac Pro look alike. So you remember the G5 PowerPC right? Remember how some variants were water-cooled? It used a DDC pump. One of the very first.

Anyway, I wasn’t actually making a direct suggestion on what you should do overall. Just providing some specific information on that side of the options to consider against the rest. Though I guess I’ll also mention, about those Enermax (specially this brand, since it was mentioned) AIOs, they do perform well, better than others for Threadripper, but even the revised models seem to have some type of contamination or corrosion problem. Gamers Nexus has some good reporting on it.

Thanks again. I had read about the Enermax issue and wasn’t really considering them.

Re: the pumps, D5 seems like a good idea. I take it that they need to be oriented in a certain direction to work properly? Like, you can’t turn it on its side or the rotor would tilt?

Many AIOs seem to combine the pump and waterblock; are there any disadvantages to this approach?

Yeah, the G5s were liquid cooled! When they switched to Intel they went to more traditional aircooled heatsinks with tall fins. I had a Mac Pro 5,1 until recently and each processor had a heatsink about the size of a box of Pop-Tarts :slight_smile:

So I think I’m leaning towards a simple solution:

  • Combo D5 + reservoir, likely EK Quantum Kinetic TBE 200? I will have to find a place for it or use one of their flat reservoir combos.
  • Alphacool Nexxxos Monsta 180mm radiator - copper and extra thick.
  • Noctua fans as you recommended
  • EK Velocity STR4 waterblock (full nickel) - or maybe the Heatkiller IV in full copper.
  • soft tubing with compression fittings

Man, this stuff isn’t cheap, but… hopefully quality lasts.

The orientation on the D5 can be upright or on its side, actually. Just not upside down.

The AIO approach works just fine with smaller pumps. There was one custom loop block that worked this way with a pump integrated, the Swiftech Apogee Drive, but that is an older design that is not big enough for Threadripper sized chips.

If you like the Quantum Kinetic, go for it. It’s a 200mm overall height res. If you wanted something smaller, The Maelstrom X50 is only 130mm. Or those flat ones, yes.

The Monsta might have bragging rights being 80mm thick (a class above all others) but it doesn’t necessarily outperform the SR-2 unless in push-pull. Also, The Dune claims to be able to fit 360mm long ones, so I would go with that.

Is there a reason you would go with the EK one?

I will really have to wait till I get the case and components to gauge how much space is available. In the LTT video it looked like he had room to install a pump like that except for his huge graphics card (not an issue with mine, the WX2100 is relatively tiny). In the video, he used an EK Phoenix (now either backordered or EOL) that just fit the space.

Yes, I would be getting a radiator that can fit 3x 120mm fans to mount up front, total height cannot exceed 400mm. If thickness is important, then this one: https://www.alphacool.com/shop/radiatoren/radiatoren-aktiv/12877/alphacool-nexxxos-monsta-360mm-radiator?c=20544

But then again LTT used the EK Phoenix with the EPYC 7742 64-core CPU, and it seemed to work OK, even near-silently most of the time (not sure what it was like when pushing their raytracing demo), so maybe there is a tradeoff between radiator thickness + fan speed / efficiency, so maybe I could start with a more standard Nexxxos radiator? Also if you watch the video the Phoenix already takes up a lot of space up front (at 68mm thick) so I don’t know if I could go twice as thick and then add fans on top of that… their use case is the top venting radiator I think, not a front-rad that doubles as the intake fans.

Re the pump / reservoir, I’m open to different D5 solutions. EK seems a reasonably reputable brand, but the Heatkiller Tube 100 D5 does look very well designed.

That’s what I was talking about, the trade-off. There is a point where the Monsta is great but its not at the push only low rpm you want to run for noise. Instead the SR-2, or even the Hardwarelabs GTX or perhaps XSPC RX360.
If there were more players in the 80mm thickness category maybe we would see more interesting results there.

Yeah. One day when I’m a zillionaire I’ll just go push-pull and stick it in a server room, but not now :slight_smile:
I will look into your recommendations, I’m learning a lot, so thank you very much!