Originally Posted by Unicr0nhunter
Originally Posted by PepeLapiu
Why would you want to change your pump speed?
I set mine at #3 and forget about it forever.
You won't notice a performance change ever from dialing your pump up or down.
+1 to this.
Flow rate is not like fan speed. It has little-to-no affect on temps until you have so many blocks of restriction that it starts to get way low, in which case you'll need more pump not a faster speed setting. Pump speed on a D5 is something to set to the highest speed that agrees with your threshold for noise and then forget about it.
There's good reason to use PWM to control a DDC pump, as they can suffer from heat-related failures if run at full speed and Swiftech's PWM implementation on the MCP35x is a pretty straightforward / reliable way to address the reliability issues that pump has. PWM D5s, on the other hand, not-so-much. For example, on the 35x if the PWM duty cycle gets low or falls to zero (for example, at startup), the pump reverts to 60% speed by default.
In contrast, the D5's PWM implementation is a bit buggy. If the PWM signal isn't present or drops below ~8% for any reason the pump will stop altogether, which is why D5s often trigger no CPU fan faults at startup
. IT Diva has pointed that out and other QC issues
with PWM D5s quite a lot recently.
Arguments about the wisdom of controlling pump speed relative to CPU temp aside . . . . If you already have a PWM pump, it is nice to be able to control it, even just to find a setting to leave it at.
Looks like you've sorta rolled the characteristics of each pump into the other. . . . .
The 35X runs at min speed, about 1300rpm, whenever the PWM percentage is less than about 15%, even down to 0, . . . . . varies a little from pump to pump by a couple percent
The D5 runs at min speed, a bit over 800rpm, when the PWM is less than a similar amount, but still above 0.
If you actually take the PWM line to 0, which means to ground, (not disconnected) the pump will stop.
Once it's stopped, you'll need to bring the pulse width above about 8% before it starts again.
I actually have not looked at how this plays out on a mobo, and if that's why sometimes the CPU fan error triggers.
I don't know if the boot process holds the PWM pin of the CPU fan header to ground during the first few seconds or not, and that possibility may differ between mobos.
At the other end of the PWM percentage range, disconnecting the PWM line to a 35X forces it to run at max speed.
This is because the pump has an internal resistor connecting the PWM line to 5V, so the control electronics see a 100% duty cycle signal.
The D5 is unique, and non standard, in how it responds to having it's PWM line disconnected . . . . .
It runs at 60% speed, and does not have the internal resistor that pulls the unconnected PWM line up to 5V.
For you guys having issues getting the PWM D5 to control from the CPU header, it may well be related to why it doesn't control from the new PWM capable Aquaero 6 either.
The issue lies in what the Intel standard for PWM fans calls for, and the way PWM is implemented in the D5.
Mobos, no doubt follow the Intel standard, and expect the PWM device to have the PWM line pulled up to 5V with an internal resistor.
Without the internal resistor, pullup, there won't be any pulse, so no control.
With the PWM Aquaero, the solution is to add a little mod at the 4 pin plug that creates a 5V source using a resistor and Zener diode, from the Gnd and 12V pins, and then puts a pullup resistor from that 5V point to the PWM line.
Here's the pic: (more info about it in the Aquaero owners club thread)
You may end up having to do the same thing to get the D5 to work from a mobo CPU header,
DarleneEdited by IT Diva - 3/19/14 at 5:21am