5 ms·

They are comparable on cooling capability except for noise levels when the CPU is overclocked. I have a big air cooler and it gets really noisy when CPU is loa

They are comparable on cooling capability except for noise levels when the CPU is overclocked. I have a big air cooler and it gets really noisy when CPU is loaded.

Skunkleton 7y ago
A downside to watercooling in general is that it has a higher thermal capacity relative to a fan and heatsink. This means that a watercooled CPU will stay hotter for longer after it is no longer under load, relative to a heatsink setup. IMO an AIO is a notch down in cooling performance relative to a large heatsink. I still went AIO for noise reasons though.
- ac29 7y ago
  Isnt the reverse also true, that it will stay cooler longer when ramping up load due to the higher thermal mass of the cooling system?
  - coribuci 7y ago
    No.
  - deleted 7y ago
    [deleted]
  - nomel 7y ago
    Yes, it’s not much different than a bowl of water being heated from one side and cooled by a heat sink with a fan on it on the other. It takes time to move the temperature of that water around with some fixed heat source/sink. Gamers Nexus has some standardized measurements for “time to max”: https://m.youtube.com/watch?v=h10MU3Jebx0&t=751 https://m.youtube.com/watch?v=h10MU3Jebx0&t=751
    - davrosthedalek 7y ago
      That's not quite the right explanation. With the pump in the loop, the heat transfer speed is actually quite high, and ideally the temperature difference between "after CPU" and "after radiator" is small. Without the pump (ie. "bowl"), the temp difference would be quite big until convection kicks in. However, cooling on any radiator is a function of the temperature difference between air and metal. The heat from the CPU will slowly heat up the water and radiator, which has actually a large heat capacity. That takes times, so the temperatures go up slower. When the heater stops, it will take the radiator also comparatively long to get that heat out of the water again. A normal air cooler has much smaller heat capacity, so will react much faster, in both directions. These faster cycles are certainly less good for the CPU than the slower cycles of a water loop.
      - nomel 7y ago
        > That's not quite the right explanation. It is for intuitively explaining how heat capacity is what causes the delay.
    - philjohn 7y ago
      The liquid in a custom loop never gets particularly hot, mine tops out at around 34c. Ideally, you want to set your fan and pump speed based off coolant temperature, which is inexpensive with a simple screw-in temperature sensor.
  - deleted 7y ago
    [deleted]
- xxs 7y ago
  >after it is no longer under load This is irrelevant entirely, as long as it stays in the desired/designed range. More importantly the higher thermal capacity allows for easier short turbo boosts which most of the load is. For sustained load, it matters only the hottest part (cores) of the cpu and water cooling is a lot better to transfer heat away.
  - deleted 7y ago
    [deleted]
heelix 7y ago
Noise is a thing. I went back to the classic open loop water cooler on my threadrippers. The RX480 (130 x 56 x 518.5mm) radiator is complete overkill for keeping a 1950x cool - only have 2 of the 4 lower db 120mm fans even plugged in. I'm to the point where I wonder if I could go a single fan or even just a bare radiator with the CPU paired with it now. Only 30C in the loop @180W TDP. (pump and radiator, longer term, will get tied to a 280w 3970x at some point this summer. Was not expecting the socket update they added with the sTR4x and 39xx series threadrippers)
- greggyb 6y ago
  You'll definitely need it for the 3970X. I run one on a Noctua NH-U14 (running in push-pull with one of their 2000RPM industrial fans and the included 1500RPM fan), and it can get toasty under sustained load. The Noctua typically tests similar to a 240-280 AIO in terms of heat dissipation capacity. It's a longer term goal to do a custom loop with 420mm+ of radiator, but I have other projects before that. I can maintain turbo under load, but it decays from a full 4.5GHz to 3.9GHz-4.1GHz under a sustained prime95 load. My primary workloads are more bursty, so this is not a big problem for me. I just don't like leaving performance on the table. Also, I cannot turn on PBO on air. It runs up to 95C and then bounces around from 90C-95C, and I'm just not comfortable bumping up against the thermal limit like that long term.
philjohn 7y ago
I found an AIO (Corsair H115i 280mm rad) wasn't significantly quieter than a large air cooler. On the other hand the custom loop I now have which has a 420 (triple 140) and a 280 (double 140) rad and includes the CPU and GPU is whisper quiet unless you're running a load that taxes both the CPU and GPU. It's actually eerie when you have it running because I was always used to that fan hum with previous builds.

They are comparable on cooling capability except for noise levels when the CPU is overclocked. I have a big air cooler and it gets really noisy when CPU is loaded.

Skunkleton 7y ago

A downside to watercooling in general is that it has a higher thermal capacity relative to a fan and heatsink. This means that a watercooled CPU will stay hotter for longer after it is no longer under load, relative to a heatsink setup. IMO an AIO is a notch down in cooling performance relative to a large heatsink. I still went AIO for noise reasons though.

ac29 7y ago
Isnt the reverse also true, that it will stay cooler longer when ramping up load due to the higher thermal mass of the cooling system?
- coribuci 7y ago
  No.
- deleted 7y ago
  [deleted]
- nomel 7y ago
  Yes, it’s not much different than a bowl of water being heated from one side and cooled by a heat sink with a fan on it on the other. It takes time to move the temperature of that water around with some fixed heat source/sink. Gamers Nexus has some standardized measurements for “time to max”: https://m.youtube.com/watch?v=h10MU3Jebx0&t=751 https://m.youtube.com/watch?v=h10MU3Jebx0&t=751
  - davrosthedalek 7y ago
    That's not quite the right explanation. With the pump in the loop, the heat transfer speed is actually quite high, and ideally the temperature difference between "after CPU" and "after radiator" is small. Without the pump (ie. "bowl"), the temp difference would be quite big until convection kicks in. However, cooling on any radiator is a function of the temperature difference between air and metal. The heat from the CPU will slowly heat up the water and radiator, which has actually a large heat capacity. That takes times, so the temperatures go up slower. When the heater stops, it will take the radiator also comparatively long to get that heat out of the water again. A normal air cooler has much smaller heat capacity, so will react much faster, in both directions. These faster cycles are certainly less good for the CPU than the slower cycles of a water loop.
    - nomel 7y ago
      > That's not quite the right explanation. It is for intuitively explaining how heat capacity is what causes the delay.
  - philjohn 7y ago
    The liquid in a custom loop never gets particularly hot, mine tops out at around 34c. Ideally, you want to set your fan and pump speed based off coolant temperature, which is inexpensive with a simple screw-in temperature sensor.
- deleted 7y ago
  [deleted]
xxs 7y ago
>after it is no longer under load This is irrelevant entirely, as long as it stays in the desired/designed range. More importantly the higher thermal capacity allows for easier short turbo boosts which most of the load is. For sustained load, it matters only the hottest part (cores) of the cpu and water cooling is a lot better to transfer heat away.
- deleted 7y ago
  [deleted]

heelix 7y ago

Noise is a thing. I went back to the classic open loop water cooler on my threadrippers. The RX480 (130 x 56 x 518.5mm) radiator is complete overkill for keeping a 1950x cool - only have 2 of the 4 lower db 120mm fans even plugged in. I'm to the point where I wonder if I could go a single fan or even just a bare radiator with the CPU paired with it now. Only 30C in the loop @180W TDP. (pump and radiator, longer term, will get tied to a 280w 3970x at some point this summer. Was not expecting the socket update they added with the sTR4x and 39xx series threadrippers)

greggyb 6y ago
You'll definitely need it for the 3970X. I run one on a Noctua NH-U14 (running in push-pull with one of their 2000RPM industrial fans and the included 1500RPM fan), and it can get toasty under sustained load. The Noctua typically tests similar to a 240-280 AIO in terms of heat dissipation capacity. It's a longer term goal to do a custom loop with 420mm+ of radiator, but I have other projects before that. I can maintain turbo under load, but it decays from a full 4.5GHz to 3.9GHz-4.1GHz under a sustained prime95 load. My primary workloads are more bursty, so this is not a big problem for me. I just don't like leaving performance on the table. Also, I cannot turn on PBO on air. It runs up to 95C and then bounces around from 90C-95C, and I'm just not comfortable bumping up against the thermal limit like that long term.

philjohn 7y ago

I found an AIO (Corsair H115i 280mm rad) wasn't significantly quieter than a large air cooler. On the other hand the custom loop I now have which has a 420 (triple 140) and a 280 (double 140) rad and includes the CPU and GPU is whisper quiet unless you're running a load that taxes both the CPU and GPU. It's actually eerie when you have it running because I was always used to that fan hum with previous builds.