PWM pump control, why?

[ZX2Slow]

Why have PWM control over pump speed, will increasing flow when load/temp is high allow for additional cooling?

[lowfat]

First off a PWM capable fan/pump can run at a significantly lower speed than one controlled by dropping the voltage. I personally never raise my pump above 1200 rpm but there is a 5C difference between 1200 rpm and 4500 rpm.

[Sparky]

I just run mine at full speed all the time. I don't find the pump loud at all...

[ZX2Slow]

I just run mine at full speed all the time. I don't find the pump loud at all...

Same here, I just bought a MCP35X2 that I plan to run at less than 100% so that it will dump less heat into the loop. I read of people controlling the speed of the pump based on core temperature but didn't see the need and though I was missing something obvious.

[lowfat]

DDC's don't dump heat in the loop. The heats dissipates through the plastic bottom of the pump.

Unless you have a highly restrictive loop running an MCP35X2 @ full speed definitely isn't recommended. Low restriction loops is what kills DDCs due to the PCB overheating.

[ZX2Slow]

The loop is just a quad MCP420-XP radiator and a Apogee HD block, I wanted some additional pumping capacity so I can add a second quad radiator, GPU blocks, mobo blocks, etc later on.

I plan on running it at 40%, ~3K RPM according to martinsliquidlab.org

[Steensen]

pwm control the pump to reduce the noise/resonance comming from the pump.
If noise is no matter for you never mind the investment.

DDC's don't dump heat in the loop. The heats dissipates through the plastic bottom of the pump.

Unless you have a highly restrictive loop running an MCP35X2 @ full speed definitely isn't recommended. Low restriction loops is what kills DDCs due to the PCB overheating.

It's because, against what many people believe, a centrifugal type pump (witch the DDC's are) consumes more energy the less resistance and greater volume it has to move.

[Martinm210]

3 reasons:
Reduced noise.
Reduced heat.
Reduced pump wear.

Necessary? No, but why not. If you build a truly silent system that does auto speed control of fans down to 600 rpm levels, pump noise will start becoming a concern and when doing idle internet type tasks, there is no reason you need max pump speeds to keep things cool.

A standard D5 vario can be dialed down to a fixed setting 2 or 3 with good results but some of us want the best of both in high performance when benching/gaming/folding no matter how small the gain is AND ultra silence at other times. PWM is a tool that can give you that and I like the idea of extending pump life by dialing speeds down as well.

My 2c, pumps and fans set at a fixed manual speed = boring. PWM is a welcome benefit for any pump, but you won't see it until you really set up auto speed control and dial idles speeds to super silent levels.