Testing one of the Weirdest Water Cooling Myths - A SLOWER Flow Rate will result in BETTER Temps?

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Outro:
Vendetta Beats - Angelus
(Custom Version)

[malcolmparkes]

Thanks, Roman, shut me up once and for all, I was convinced there would be a bigger difference, thanks for proving me wrong, I love science.

[gio]

The timing of this video is perfect, just bought the parts for my custom loop

[bigbenk]

Been there, studied that. A good (high) flow rate creates turbulent flow, which reduces the boundary layer, which improves heat transfer.

[JMUDoc]

It's interesting that doubling the pump speed from NORMAL only reduces CPU temps by 0.4 deg... so much noise for so little effect.

[esra_erimez]

Gamer Nexus put windows into the cpu block and radiator. And now this. You guys are awesome.

[markvvelsen]

Thanks Roman! I was really struggling to set my pump speeds in this hot weather and what would be best.

Great timing and very useful as always.

Give Shiek a hug from me!!

[CuttingEdgeRetro]

This argument dates back to the earliest years of PC enthusiast watercooling. I still remember having this argument with a guy at a lan party back in 1999 when he was convinced low flow rate and a rad between each part was king. haha XD

[waldolemmer]

I'm a GN viewer and I'm here to pester you!

[roberthelcher]

I always wondered which was better low flow or higher flow. Thank you for the demonstration. I love your amazing content.

[merrychristmas]

I'm getting ready to build my first loop and am so glad I found this video. Thank you!

[jscrub]

How do you not have more sub's. The work you put in is amazing, thank you for everything you do.

[dandel]

I think some people forget why water cooling is even used in the first place. It's either to get the most performance possible with high fan and pump speeds and the noise that goes with that. Or its for keeping the system cooler than air can at a low noise level.
The more important question is, how much flow is required for the waterblocks used to function correctly and how much radiator capacity is needed to cool the components in the loop.
I would be interested to see the same test used on a cross-flow style of radiator, just to see if the temp drop is higher or flow restriction is less. Thick vs thin rads would be a cool test as well.

[simondale]

Good video, having experimented with loop order, I can confirm, As long as your flow rate is high, loop order makes very little to no difference. But when you have multi GPU and CPU in the same loop, flow rate can be an issue, ( avoiding the expense of large tubes fittings, multi pumps etc) loop order can have a small benifit.

[chesterfield]

Thank you for testing this. It solidified the reason why i always run my pump at full speed // the aquasuite seems to be an amazing tool // i think i made the wrong decision with the corsair commander pro

[zpnk]

I'm running my pumps at around 60%. Because as der8auer says, you can't hear the pump. But the gain in lower CPU temps with running the pump at 100% is so minimal that there's no reason to do so

[JoeBob]

I watched this video a few weeks ago when I just had a normal old Magicool pump and no temp sensors. I've since got an XD5 pump, and an additional water temp sensor and I've been messing around with it for a few days, and now this video makes a bit more sense to me. Probably because I have my own system for reference.
I have a temp sensor at the inlet of my radiator, and one just after it (in the pump), and I'm seeing similar results to this.
But what I find really interesting is that it seems like every system will have it's own perfect cooling configuration. Basically it's something like if you call the heat from your components (the heat that's transferred to a chunk of water) "H", then you have to remove that H by the time that water gets back to the pump.
So basically your fans have to run at a particular speed to achieve this.
But that also depends on how long that chunk of water is in the radiator, and so it also depends on the pump speed.
So, it's like a fast pump speed is good for removing heat from components, but it's bad for removing heat from the water.
And contrarily, a slow pump speed is bad at removing heat from components, but it's good for removing heat from the water.
And of course when you have more radiators, and/or larger radiators, you can afford to run the pump a bit faster and your fans a bit slower, depending on the noise from each.
I suppose the best way to go about it is to stress your components and equalise your temps. And then gradually drop your fans and pump speed until you hit a barely acceptable temperature, and then tweak the fans and pump from there to see how the temps change.

[CidiousX]

Finally! it's the same thing I figured from my own testing and it just does not sink in with people's logic.. Thanks for your clear explanation. It's a simple link to your video from now on when this discussion comes up.

From your test results you can already see there is a sweet spot where efficiency for raising pump speed lowers. The trick is to find that speed spot for your setup and pump. Where temps are lowest vs the noise and find that drop off spot. In your video you can easily see that the benefit with going from 2000 to 4800 rpm is just 0.4 degrees celcius which probably means around 2000 RPM or even lower is the sweet spot. Raising the pump speed too high is raising noise and heat the pump emits itself. Which is obviously also counter propuctive. But it depends on the loop's components. How restrictive they are and how many etc.

[fermitupoupon]

For some reason I now want him to compare having 2 120mm radiators parallel versus a single 240mm U-flow and a 240mm X-flow radiator.

[Grinay]

Thank you for clarifying that you do not need that much flow rate to keep the loop at constant temperature, now I can disregard the people that tell me I should try to target 120 l/h.

[brainiac]

Finally someone had the balls, and the brains, to demonstrate this! Thanks Roman!