Cooling video card pwm header hows it work

Hey all wondering if anyone can explain to me how pwm works on a video card is it controlled from the video card BIOS or does the motherboard control the video card fan speed?
Getting ready for my first water cooled build and was wondering about controlling the pumps via a sunbeam pwm enabled fan controller. If I plug the fan controller into it then then the pumps into the fan controller will the seperate pumps work at different speeds controlled by mobo BIOS temp reading? or will all pumps work at same speed depending on CPU temp? Video cards generally run hotter so if its the latter I don't think it work to well. I am guessing a pwm header on a video card would not power a pump so was wondering if there was a powered pwm cable I could run from video card header to pump?
Oh my video cards are 6950's and the pumps are the mcp35x motherboard is gigabyte P67a-UD7-B3 and 2600k CPU.

 

Don't run it from the card! Needs more power than it could provide.

First and foremost the video card BIOS dictates fan speed.

 

Was just reading on another forum those pumps have the pwm connector and a seperate cable for power is that correct if so that would make it simple to connect up.
Edit just got the manual and does indeed have two seperate cables one for power one for pwm. So power is not a problem will the video card control the pump speed or will it not recognise it and not work at all?

 

I find your questions a bit confusing but no, you can't control a pump from your graphics card fan port and it is not even worth looking for the current boost circuit you would need in order to do so.

You must check the current rating of the pumps. A motherboard fan header delivers about 1 amp and if the pump is rated at or below then it would be ok to power 1 pump from one fan header directly.

I have an EK DCP 4.0 and that is rated at 1.8 amps. An idiot friend of mine ignored my warning not to plug the EK to his mobo fan header and after 6 months the fan header blew. He has a different mobo now and i guess he would listen in future when I warn him about overload.

As long as the pump current rating is below that of the fan controller or mobo then it's ok.

I use the free Speedfan software to control fans for my water rad and case. If you're pumps can be powered from the mobo fan headers then you could control those using either the software that comes with your mobo or speedfan. I prefer speedfan because it allows me to control any fan based on any temp which can be for example... speeding up this or that fan or pump based on the temperature of GPU (speedfan can access your GPU temp).

You can also set speedfan to shutdown your PC in the event that a pump or fan fails.

 

This is the pump I'm talking about http://www.swiftech.com/mcp35x12vdcpump.aspx in the manual it says to plug one wire into a molex connecter and the other wire into the CPU fan header which will then allow the motherboard BIOS to control the pump speed.. I'm guessing it does not draw any power from the pwm wire and probably has the wire which normally gives a fan its power removed. And instead gets its power from the molex connector. Pretty sure I'm on the right track but not sure if a video card header will control a pump or if it will fail to recognise it and not work at all. Don't want to argue just stating what it says in the manual.

 

OK found my answear here http://www.overclock.net/t/1220895/problems-with-recurring-bubbles/10 block on this page is running them off his gtx470 so as long as gigabyte has not used a proprietary pin out I should be good to go when the time comes I will strip my video card for a closer look will be a while yet. Cheers and thanks.

 

Quiet PC sell a VGA PWM Adapter A lot depends on whether the fan header is accessible with a block fitted.

 

As luck would have ( I was cursing it yesterday) I have to use a universal block on my card as it is non reference model and there are no full coverage blocks for it. So I miss out on a full coverage block but gain pwm control perhaps that's why it was hard to find the info I needed as the blocks of choice are full coverage which block the header. Thanks for the link hopefully they will work with my card.

 

The VGA PWM header cable is useless and pointless because it makes no sense powering a fan or pump from the GPU fan header. GPU fan controller is set for low fan speeds even when the GPU reaches 70c+ You could modify the GPU fan profile using EVGA Precision but why? Get a pump or combined fan/pump controller. If those pumps are PWM then I guess you can feed them a PWM signal from a mobo fan header so then you can use speedfan to control pump speed based on GPU temp.

I run my 2 pumps at full speed but the pump speed is sent to the PC so I can monitor it and I can set speedfan to shutdown PC fast if a pump stops working.

The pumps you want need 1.5 amps so you'd need either a fan controller capable of driving them or a dedicated pump controller.

You really need to forget about driving a pump from the GPU fan connector because it's a really stupid and pointless idea.

http://www.specialtech.co.uk/spshop/customer/Pump-Controllers-cid-2086.html

Pump and fan controllers.

 

What I gathered they they used speed fan to smooth the highs and lows and for less aggressive pump speed to avoid air in the system. I guess you could use a splitter and have them all connected to the CPU header as well and use speed fan. For speed fan don't the pumps have to be online to the motherboard how else would speed fan see the pumps? And for the umpteenth time I am not trying to power them off the VGA pwm header it is only to control the speed. Note these are pwm pumps not standard run of the mill pumps.

 

How do you get your pumps to show up in speed fan do you use some USB pump controller or a motherboard header?the post I took particular notice to was by caleal.

 

Whole idea of pwm connection is so the pumps don't run flat out all the time the speed varies with temps automatically rather than manually turning a knob on a fan controller.be it either by video card/mono BIOS or speed fn I will cross that bridge when I get to it. It also saves having to buy more hardware if I can utilise the pwm output on the video cards. CPU and motherboard blocks off CPU header and via a splitter to two seperate pumps and a seperate header on each video card for the other two pumps.

 

I don't think many people understand how the 35X work. They're powered from a molex and use the PWM signal for pump speed control.

It depends on whether Speedfan can detect the sensor on the Graphics card as to whether you can set up a fan/pump profile for it. You can create a fan profile in Afterburner which would do the same thing but probably a lot easier.

I use Asus Fan Xpert for my pump control because it's easy to set up a user defined profile. Despite what was said in the Overclockers thread you can use Fan Xpert to set up a gently increasing pump speed rather than have abrupt steps.

With GPU's being less sensitive to higher temps you may find you can run the pump at a lower fixed speed. Alternatively as has been suggested and if you assume that the CPU load will be increasing when the GPUs are loaded you can use the CPU PWM header. I control 2 35X with PWM by using a splitter cable.

Edit: My 35Xs generally run at around 1700rpm when the system is under a low to mid load and are only set to ramp up to higher speeds when there's high load on the CPU. Even with 7 blocks in the loop the pumps don't need to run above about 3000rpm (Max rated speed is 4400rpm although the do hit 4500rpm).

 

Yea that's what I thought. So as long as the software can control the header on the video card I can control the pumps using those headers. Cheers and thanks I'm out. One last question will fan expert shutdown pc in case of a pump failure?

 

Speedfan detects GPU temp. I have it set to increase rad fans when GPU heats up (40c is max temp my 680 reaches now). My rad fans are connected to CPU PWM fan header and there are 5 of them on one header. Not a problem because the Arctic fans plug in to each other (chain) and 6 of them consume below 1 amp total.

You can set speedfan to control fans/pump based on any temperature such as hard disk, case, GPU or anything connected to a mobo fan header.

 

Which is what I have been getting at but instead of just controlling the fan speed you can also control these pumps the same way if speed fan can control gpu fan speed than I will be able to control the pump.

 

Yup, that will be pretty neat.