Question AIO pump okay below 100%?

NzSkux

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Hi all,

Got a Kraken x73 yesterday and it's cooling much better than my DH15 air. Very happy with it except for the audible ticking on pump at 100%..

I'm on the spectrum and quite sensitive to sound, especially high frequency. I don't mind it running at 100% when gaming as I have my headset on but it is quite annoying and loud with no headset and just browsing. It's not noticeable under 75% rpm.

I've read you should always have it at 100% and am wondering if having it at 75% could cause any long term issues with a slow water flow etc

Thanks all
 

Lutfij

Titan
Moderator
If you reduce the flow, you need to compensate that with higher fan RPM's, finding a balance to the fan RPM and pump speeds that are both not annoying to you(or is audible) is what you need to tinker with. As a baseline, for AIO cooler, yes you're supposed to have the pump run at 100%, though I am curious, how are you manipulating the pump speed? CAM?
 

Phaaze88

Titan
Ambassador
The reason for maxing the pump rpm is that doing so yields lower overall temperature swings under low loads, which are responsible for fans ramping up and down sometimes with core temperature spikes.

Though you could just go into bios and raise the lower and middle temperature limits a little. Some motherboards have their defaults pretty low. Mine were at 20 and 25C respectively. I raised them to 40 and 55C instead.
 

NzSkux

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If you reduce the flow, you need to compensate that with higher fan RPM's, finding a balance to the fan RPM and pump speeds that are both not annoying to you(or is audible) is what you need to tinker with. As a baseline, for AIO cooler, yes you're supposed to have the pump run at 100%, though I am curious, how are you manipulating the pump speed? CAM?
Thanks for the response. I have full speed set in bios and am using CAM (I know CAM will override it). I have it set to performance mode with a custom curve, 60% speed till 60 degrees then 100% after 60 degrees.

The reason for maxing the pump rpm is that doing so yields lower overall temperature swings under low loads, which are responsible for fans ramping up and down sometimes with core temperature spikes.

Though you could just go into bios and raise the lower and middle temperature limits a little. Some motherboards have their defaults pretty low. Mine were at 20 and 25C respectively. I raised them to 40 and 55C instead.
Thank you I'll check this out
 
If you reduce the flow, you need to compensate that with higher fan RPM's, finding a balance to the fan RPM and pump speeds that are both not annoying to you(or is audible) is what you need to tinker with. As a baseline, for AIO cooler, yes you're supposed to have the pump run at 100%, though I am curious, how are you manipulating the pump speed? CAM?
ummm....don't see how increasing fan speed compensates for lowered water flow since increased air flow can't remove heat from water that's not being carried to the radiator.

Maybe you're thinking of water's exceptional capacity to absorb heat? So at a lowered flow, it just starts running hotter (absorbing the heat still) so faster fans would remove it faster? That's interesting theory...and maybe a thermodynamics engineer could figure out that relationship.

But I agree...pump speed should be 100% all the time and very quiet doing it. If a Kraken's pump is loud enough to trade off noise with the fans...ummm...tell me again why Nzxt is a such a premium brand?
 

NzSkux

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ummm....don't see how increasing fan speed compensates for lowered water flow since increased air flow can't remove heat from water that's not being carried to the radiator.

Maybe you're thinking of water's exceptional capacity to absorb heat? So at a lowered flow, it just starts running hotter (absorbing the heat still) so faster fans would remove it faster? That's interesting theory...and maybe a thermodynamics engineer could figure out that relationship.

But I agree...pump speed should be 100% all the time and very quiet doing it. If a Kraken's pump is loud enough to trade off noise with the fans...ummm...tell me again why Nzxt is a such a premium brand?
Sigh. I really don't want to have to return it.

Lets say I leave it at 75% when not gaming and 100% when gaming. Would this cause immediate damage? I'm not fussed if it only lasts a year or two
 

Phaaze88

Titan
Ambassador
Lets say I leave it at 75% when not gaming and 100% when gaming. Would this cause immediate damage?
Not at all. In fact, it's better for the motor when it's set to a flat curve. I have my Eisbaer Aurora and Celsius S36 set to 85%. That extra 15% didn't seem to amount to jack; I guess once it's already in the 2000s, it doesn't matter as much.
You're not really putting any heat into the loop until gaming comes anyway.

I say, go ahead, do the 75% and see how it goes. Not a big deal - it's a harmless experiment.
 
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NzSkux

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Not at all. In fact, it's better for the motor when it's set to a flat curve. I have my Eisbaer Aurora and Celsius S36 set to 85%. That extra 15% didn't seem to amount to jack; I guess once it's already in the 2000s, it doesn't matter as much.
You're not really putting any heat into the loop until gaming comes anyway.

I say, go ahead, do the 75% and see how it goes. Not a big deal - it's a harmless experiment.
Chad. Thanks for peace of mind.
 

Paperdoc

Polypheme
Ambassador
No real problem with your plan. A couple notes to help.

A few AIO systems do allow you to set your own pump speed using their software tools. Without considering your particular concern with noise, the general guidelines are these. Don't fiddle with the speed frequently - let the rad fan speeds do all the real control of CPU cooling. Use the pump speed as a "ranging" tool. Try to select a speed so that, at max workload (and heat generation) the rad fans can still keep your CPU cooled without actually running full speed (their upper limit). Your plan - to change pump speeds between two general classes of workload - is not too frequent, so go ahead. In your case, the speed choice WILL be affected by the noise consideration, just as long as you don't limit the cooling available for max workloads.

The other item is HOW? Many systems are designed for always full pump speed and it can be difficult to change that. YOUR Kraken X73 system has NO way for the mobo headers to alter pump speed. The pump power is always fed directly from the PSU via a SATA power output connector. The pump speed MAY be adjustable within the CAM software utility - I don't have that so I cannot say. But that is the only tool you would have for changing pump speed and observing what it is.
 
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NzSkux

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Jul 5, 2021
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530
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No real problem with your plan. A couple notes to help.

A few AIO systems do allow you to set your own pump speed using their software tools. Without considering your particular concern with noise, the general guidelines are these. Don't fiddle with the speed frequently - let the rad fan speeds do all the real control of CPU cooling. Use the pump speed as a "ranging" tool. Try to select a speed so that, at max workload (and heat generation) the rad fans can still keep your CPU cooled without actually running full speed (their upper limit). Your plan - to change pump speeds between two general classes of workload - is not too frequent, so go ahead. In your case, the speed choice WILL be affected by the noise consideration, just as long as you don't limit the cooling available for max workloads.

The other item is HOW? Many systems are designed for always full pump speed and it can be difficult to change that. YOUR Kraken X73 system has NO way for the mobo headers to alter pump speed. The pump power is always fed directly from the PSU via a SATA power output connector. The pump speed MAY be adjustable within the CAM software utility - I don't have that so I cannot say. But that is the only tool you would have for changing pump speed and observing what it is.
Thank you for taking the time to respond.

I am using CAM to control the pump at the moment. Using ASUS Armoury Crate to control rad fan speeds, until my fan controller arrives. I'll do a few stability tests and fiddle with the balance
 

Karadjgne

Titan
Ambassador
Cam and that pump and fans are designed for variable speed operation, there's no point in running the pump at 100% for idle as an example, the cpu isn't going to care if it's 32°C or 34°C.

My X61 I just set for Silent mode, temp by coolant not cpu and let it be, regardless of actual reported temps. And that was a i7-3770k at 4.9GHz OC.

As the coolant temp rises, so does flow and fans, according to the curve, which moderates the temps, which is what coolers are for, not trying to obtain useless maximum lows.

Maybe you're thinking of water's exceptional capacity to absorb heat? So at a lowered flow, it just starts running hotter (absorbing the heat still) so faster fans would remove it faster? That's interesting theory...and maybe a thermodynamics engineer could figure out that relationship.
Yes and no. As the coolant is forced across the microfins, it picks up the transmitted wattage given off by the cpu. The lower the flow, the longer it takes to move the pressurized coolant across the fins. The cpu is still dumping the same wattage, but the coolant has a far higher capacity than the cpu has output ability. Take a pan of water, put it on the burner on High for 1 minute. Temp didn't move, even though it just absorbed 1500w for 60 seconds. Same test, 2 minutes. That's 3000w total, nothing changed.

But, that still really doesn't affect coolant temp much, nor change cpu temps. What does is the transmitted temps to the tubing, the fittings, the piping in the rad. As they get warmer, so does the coolant, eventually. As the coolant heats, it looses a little efficiency, fans/pump move faster to compensate.

That wattage is carried by the coolant, but has very little affect on the liquid. When it hits the heat exchanger (rad), that wattage is absorbed by the metal fins, and turned into heat, which the fans try to dissipate. Faster the fans, more air is moved across the fins surface area, higher the rate of dissipation. Upto a point.

But there are points of uselessness, same with an aircooler, above a certain amount of wattage there's nothing to dissipate. Like having a D15 at full blast on a cpu at idle, turning it down to 50% makes for zero change because the first 30% is all that's necessary, any rate above that doing nothing but create noise.

So Cam was designed to lower pump speeds, lower fan speeds down to that point, being just enough to efficiently move the wattage from the microfins to the rad. Aesthetics. No point in running maximums with all its noise or potential noise, for no reason.

If you open a program and the temp jumps to 70°C, then settles down to 55°C, so what. Same temp, almost identical cpu performance. Having Cam set for cpu speeds means an instant ramp to 100% (default for 70°C) and 3 seconds later that drops to a more moderate % for the 55°C. If Cam is set for coolant temp, no ramp at all. Pump and fans don't change speeds because the coolant hasn't changed temps.

Coolant usually hits max somewhere in the 40° to 50°C range, and starts at case ambient temps, so somewhere around 30°C. That gives only a 20° range for change, so in affect is quite sensitive, just not fast to change, can take a half hour to go from 30° to 40°, especially in the bigger coolers with higher coolant volume.

For an aircooler, a jump from 32° to 34° is negligible, aircooler having upto a 70° ish Delta (cpu 30-100°), so 2° is a measly 2.8% change. Nothing really. For a liquid cooler, a 2°C hike is a 10% change in temps (30-50°C coolant) which is significant.

So fan/pump speeds will raise along the curve much faster than an aircooler, having a far lower curve to move on.

All of which means just set Cam for Silent or Standard and stop worrying about the exact cpu temp, you have a liquid cooler not an aircooler and as long as temps stay within safe ranges it really does not matter what they are.
 
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