[SOLVED] Does lowering the speed of a 3-pin AIO pump going to break the pump?

[Ratteus]

I've found a setting that can enable the control of a 3-pin AIO pump speed by using the DC mode in the BIOS. So, it's controlling the speed by lowering the DC voltage going to the pump, right?
My question is, does lowering the voltage going to the pump going to break the pump? I've read quite a few articles about how a 3-pin AIO pump
should be running at 100% all the time, but I just want to extend the lifespan of AIO as long as I can. Am I going to break it instead?

 

[Dragos Manea]

Depends, what AIO you have, some have controlling software

 

[CountMike]

I've found a setting that can enable the control of a 3-pin AIO pump speed by using the DC mode in the BIOS. So, it's controlling the speed by lowering the DC voltage going to the pump, right?
My question is, does lowering the voltage going to the pump going to break the pump? I've read quite a few articles about how a 3-pin AIO pump
should be running at 100% all the time, but I just want to extend the lifespan of AIO as long as I can. Am I going to break it instead?

In AIO pumps motors are not directly connected to pump's impeller so it doesn't really matter what speed they are running. Motors work same as in fans. Only "danger" could be if pump and it motor overheats because of slow liquid circulation but that would also overheat and shut CPU down first.

 

[Paperdoc]

One major reason for having an AIO pump run full speed all the time is that it needs to run at some CONSTANT speed all the time. In such a system, TWO factors affect how fast heat is removed from the CPU - the speed of the PUMP that moves heat to the rad, and the speed of the FANS that move the heat from the rad liquid into exhausting air. If you try to have BOTH of those factors changed automatically in response to CPU temperature, they "chase" each other. That is, one cools the CPU down a bit too much and then both of them try to slow down and overdo it but with different response times, then temperature starts to change and both items also change, one out-doing the other again, and it becomes a MESS! The simple solution is that ONLY the FANS respond to CPU temperature, and the PUMP only guarantees a fixed rate of transport of warmed liquid.

In such a system, MOST of the time the rate of fluid flow around the loop is MORE than is needed. In that situation setting the Pump to run slower has no big impact as long as you set the pump speed and LEAVE it there. The fans will compensate by speeding up slightly. The real impact of fixed LOWER-than-spec pump speed is when you get to max workloads and heat generation. Then it is possible that the fans running at max speed can not remove the heat fast enough because the heat is not being carried to the rad fast enough. If you are confident this effect is NOT going to limit your cooling system at max workloads, a slower-than-full-speed setting on the pump does no harm, and may prolong the pump life a little.

 

[Karadjgne]

The pumps used in AIO's generally tend to have lower flow and lower head pressure than a DDC or D5 pump to begin with. That's important because AIO's also tend to have smaller inner diameter hoses as well. Which builds up resistance and lowers flow volume.

So what you end up with is a very non-linear slowdown when you lower pump rpm. Cutting voltage from 12v to 10v is a 17% drop in rpm, but can easily be a 50% drop in flow as a result.

That lowers flow over the pump head, which raises the amount of energy absorbed in the coolant which means when it hits the rad, the fans must be able to dissipate all that extra energy or it remains, and heats up the coolant, which lowers the efficiency of the coolant, and temps of the cpu go up.

 

[Paperdoc]

Thanks for Best Solution.