G1.Sniper5 CPU OPT (PWM water pumps)

[wibujo]

I Have 3 PWM pumps in my RIG (EK-BAY Res Dual DDC 3.2 PWM Serial and EK-DDC 3.2 PWM X-Top CSQ) The problem is they run at full speed. I run the radiator PWM fans on the mobo CPU fan header (these are OK) and I run the pumps on the mobo CPU OPT header (they will not idle down) I tried to make adjustments in the BIOS for the CPU OPT Speed Control setting with no luck. Any help with this problem would be much appreciated.

Thanks, wibujo

[danny26501]

Re: G1.Sniper5 CPU OPT (PWM water pumps)

mismo problema x99 G1 Wifi

[parsec]

Re: G1.Sniper5 CPU OPT (PWM water pumps)

Several possible reasons for your problem:

+ The PWM splitter cable you are using for the pumps is not wired correctly. Only one of the pumps should be sending a PWM speed signal to the board, which depends upon the cable being wired correctly.

+ Some PWM controlled devices put an excessive load on the PWM speed control signal, which causes the signal to fail, and the PWM devices run at full speed. The usual limit for PWM fans is ~six fans on one PWM header speed control pin, but a few PWM fans are known to be limited to ~three fans.

To test both of these possibilities, connect only one pump to the CPU OPT header directly (no splitter cable) and see if its speed changes. If the speed does change, try two pumps with the splitter cable. If that works the splitter cable is fine. Add the third pump, if you loose the speed control, three pumps are to much for the board's control to handle.

The above test assumes you set the CPU OPT fan control to Manual, and tried the various PWM speed settings that are available. You could also try the other CPU OPT options when using one pump to see if they have any effect.

+ The CPU OPT header is actually not a true PWM controlled header. The manual shows all the four pin fan headers except the CPU FAN header as having the fourth pin labeled "VCC", which is not the same as the CPU FAN header's fourth pin.

Unfortunately, this reason is probably why you cannot control your pump speeds. I've seen posts in other forums complaining about CPU OPT headers on many boards that don't control PWM fans correctly. Trying a single pump on the CPU OPT header while trying different settings in the BIOS will show if this is true.

OTOH, I have seen a different water pump for PC cooling that was supposed to be designed for PWM control, which never changed its speed regardless of the settings in the BIOS, when it was connected to the CPU Fan header, known to work with PWM fans.