I need suggestions for a demanding CPU watercooling solution - probably a suggestion of "custom loop" components.


I just outgrew my 12 core overclocked CPU and upgraded it to an 18 core i9-10980XE. (I do a lot of very intense CPU work.) My Noctua NH-D15 can't handle the output, and tops out at about 4.1 GHz (overclocked) whereas most cores pushed individually can run as high as 4.7 GHz (if the cooling is adequate). So the cooler greatly limits what I can do with the CPU.

I think I need a loop that can reduce the OC temps by about 25 C from those the Noctua can achieve (so that OC currently hitting 100C on the Noctua only hits about 75C on watercooling). I.e., reduce a delta-T of about 70 to a delta-T of about 45 (or ideally even less, under 40 C).

That's a hell of a drop. It suggests I need custom loop not AIO, and probably good kit at that - a very good 360mm copper radiator, and a high flow rate pump. But it should be possible.

General info

  • System: i9-10980XE, Asus WS SAGE X299, 128 GB 3600 RAM, very basic old VGA card (not used for gaming), EVGA Supernova G2 1000W PSU, Samsung NVMe system+data SSDs. System runs 24/7 for weeks to months at a time (offline), so stability and not needing to interrupt often, matters.
  • Price/quality: Price is not important, although "cheapest possible" is good. Quality, reliability and performance are key.
  • Kit vs. custom loop: I am OK with kit or custom, but suspect I'll need to choose individual components.
  • Experience: I've been building custom PCs and custom enclosures for a long time. I've never used water cooling before but I'm familiar with it; it doesn't scare me.
  • Leaks: I am quite nervous of leaks. The pump/reservoir/radiator will be "standalone" outside the chassis, so if they leak or I move the computer on its side, it's safe. So it's only the CPU block and connectors that are a concern for leaks.
  • Loop length: The external pump/reservoir/radiator means I need to allow a total loop length of up to 2.0m (2.5m max).
  • Noise: Not especially worried about fan and pump noise as long as they don't sound like a howling gale.

Component criteria

  • Radiator/pump/reservoir: I expect I will need a very good (thick?) 360mm copper rad, and a large combined very high max flow rate durable pump-reservoir.
  • CPU block: This is the one component able to leak inside the case. So I want it really well engineered for LGA-2066 heat flow and water connections, whatever way is absolute most sure to avoid leaks, since it will run 24/7. Happy to get a premium product, if it has functional benefits.
  • Fluid and tubing: I don't care about aesthetics and looks. My kit is functional and quality, not "pretty". So I would like a fluid and tubing that as little as possible causes sediment, degrades over time, etc. Would aim for flexible tubing with anti-kink. No preconceptions about ID/OD thickness.
  • Connections: Must be very good and once tested initially, very hard to "go wrong". I don't want to buy another £2000 CPU/motherboard/RAM here!
  • Redundancy/continual operation: If the reservoir can't be topped up while in use, then I would consider a 2nd pump or reservoir in parallel, with shutoff valves, so I can top up one while the other is in 24/7 use.
  • Materials: For the loop gneerally, whatever's needed to avoid sediment/plastic deposit and not have to maintain often. For the metal components, no "mixed materials" electrolytic contact with the water, so probably copper/brass not aluminium.

Existing recommendations

I've been advised to look at EK for everything except the radiator, and get a thicker radiator from someone else who makes them, such as Thermaltake. But it's hard to find good reviews and advice.

What are my options? Is my goal realistic?

Help appreciated!

  • Are you 100% determined to have everything but the CPU block externally? Is that just out of fear that something might leak? It is doable, but especially the pump/reservoir mount won't be pretty. Pump flow rate is not as important as you might think. Usual water cooling pumps like a DDC at ~40% will work fine. What counts more is radiator surface area. Instead of a very thick 360mm radiator, I would recommend something like a MO-RA3 360. Topping off the fluid regularly should not be necessary at all outside of regular maintenance. Otherwise, you have an actual leak.
    – user13807
    Commented Apr 17, 2020 at 18:39
  • I'd like to, but as much functional purposes as leakage. A custom stand for a standalone rad/pump/reservoir means zero warm air interaction with the enclosure (coolest ambient air), and reduces the weight a lot if I want to move the chassis or rotate it on its side while running, as sometimes happens. The loop length means I can do that without the heavy cooling gear being inconvenient. (My file server has an external 16 x 3.5" custom HDD chassis for similar reasons - cooling, airflow, vibration deadening, and I'm very happy with that so I know this is OK for me)
    – Stilez
    Commented Apr 17, 2020 at 18:44
  • @MechEng - What a monster that rad is! I'm not sure I need that much. I need to disperse ~500W (~380W + 30% safety margin). That one looks closer to 900W, and not as easy to find space for. No doubt it would do the job, though!
    – Stilez
    Commented Apr 17, 2020 at 19:32
  • It may look like overkill, but that's what is usually used for external radiators. It has a sturdier frame, and there are accessories like stands and reservoir mounts for it. Which means less DIY for you. And the footprint is the same as smaller radiators. With your goal of cooling a 10980XE overclocked to the max, I would not go much smaller if you want the solution to be quiet. Your goal has to be getting the water temperature as close to ambient as possible, and this is the most common solution.
    – user13807
    Commented Apr 17, 2020 at 19:50
  • Interesting and helpful! Do you want to expand this into a fuller answer, or just stick with the radiator part only? Also, if I did decide to go for a more traditional 360-420 x 120-140 format, do you have any suggestions for really good performers?
    – Stilez
    Commented Apr 17, 2020 at 19:55

1 Answer 1


If you want an easy all-in-one solution, Alphacool has you covered: Alphacool Eiswand 360
complete set: https://www.alphacool.com/shop/new-products/21360/alphacool-eiswand-360-cpu-black
radiator/pump unit only, currently not available: https://www.alphacool.com/detail/index/sArticle/22164

The set has everything you need in one ready to use package, which makes this quite a compelling deal at 350€. The radiator is a full-copper triple 120mm unit with 45mm thickness. Combined with the 6 included fans in push/pull configuration, it should provide enough cooling for your needs, albeit at a slightly higher noise level than an even larger radiator might allow. This solution even has two pumps for redundancy, just what you wanted.
You can either power it through your system, or with the included power supply.

Alphacool, if you never heard of them, has a pretty good reputation in the water cooling business. They usually offer decent quality products at a reasonable price point. I used one of their their AIO water coolers in the past, and my last custom loop was built with their fittings and radiators. I have nothing negative to say about the quality.
And the reviews for this particular unit are pretty good too

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