Gigabyte PWM fan wiring question - with pictures!

[amazingrando]

I have a couple of these Gigabyte 5850 OC cards (which I hate - the cooler is crap):



Today one of the fans literally fell off.  The other one is not in much better shape.

I have two brand new fans of the exact same model (used in Asus DirectCU 5850's)

I'm trying to figure out the wiring.  It seems that the 4-wire PWM wiring is as follows:
Pin    Name    Color
1    GND          black
2    +12VDC     yellow
3    Sense       green
4    Control      blue

On the Asus fan, it has these four wires and a 4 pin connector.


On the Gigabyte card there are two fans in a master/slave configuration.


The slave appears to just have 12V DC (red not yellow) and a black ground wire.  The master appears to have ground (black), 12V DC (red), and a third wire.  Would that third wire be sense or control?  I'm guessing it's sense, which would be green on the Asus' 4-wire configuration




The other question is whether the Asus fan, which has all four wires, will work fine if that missing wire is not connected to the fan?  The Gigabyte connector is only a three pin.  I'm assuming it would work fine - similar to a 3 pin system fan on a 4 pin header.

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[jake262144]

Yellow (that 'third wire') is sense.
You can use the ASUS fan safely as long as you don't botch the cablology.

That cooler is not necessarily crap, be advised that heatpipe orientation can make one hell of a difference.

[malevolent]

Yellow (that 'third wire') is sense.
You can use the ASUS fan safely as long as you don't botch the cablology.

That cooler is not necessarily crap, be advised that heatpipe orientation can make one hell of a difference.

I actually have two 5870 with same/similar cooler and it only cools the GPU well with fan @ 85% (only ~3.2k RPM, they aren't fast), VRAM modules and VRMs get pretty hot.
but thanks for the link, I did notice a difference of several degrees with different orientation, even though the card now gets a bit of warm PSU exhaust air and gets probably slightly warmer inhaust air because there are cables close to the fans. In a seemingly better position (-90deg) the temperatures were worse (5-6C).

[amazingrando]

Yellow (that 'third wire') is sense.
You can use the ASUS fan safely as long as you don't botch the cablology.

That cooler is not necessarily crap, be advised that heatpipe orientation can make one hell of a difference.

Thanks!  I didn't want to start cutting up wires without knowing what was what.

Interesting link about the orientation.  Mine are mounted vertically, but I'll fiddle with that.  Even if orientation does help other coolers seem to work well regardless of orientation, which in my book is crap. 

[jake262144]

Ummm... there are actually two links - you need to pass a perception check (6 perception required) to notice that the two words underline independently when hovered over 

The order fan wires are connected in was designed for maximum compatibility: 4-pin fans can be connected to 3-pin fan headers (the blue PWM wire remains disconnected) and vice versa.
Black always means neutral and must be connected.

[Cablez]

Its weird but on my GB5870 the master and slave fans both had three wires.  I just used ebay sourced replacements to fix it.

I will need to test that heatpipe orientation though because that cooler is garbage. 

[amazingrando]

Ummm... there are actually two links - you need to pass a perception check (6 perception required) to notice that the two words underline independently when hovered over 

Haha.  Without the underlining of a link it looked like it was one link.  I would have never known if you hadn't mentioned it

The order fan wires are connected in was designed for maximum compatibility: 4-pin fans can be connected to 3-pin fan headers (the blue PWM wire remains disconnected) and vice versa.
Black always means neutral and must be connected.

That's what I figured.  I'll give it a try tonight and see what happens!

[amazingrando]

Ok, I got it all put together and it works!     Here's the wiring:



And here it is all assembled - I like the Asus fans on the Gigabyte GPU.  haha

[Cablez]

Looks good rando.  Have you tried it yet?  I noticed that the slave fan on mine does not spin up in idle mode but only kicks on when the gpu is stressed.  Have you seen this behavior, as I thought the fans should always be running?

[amazingrando]

Looks good rando.  Have you tried it yet?  I noticed that the slave fan on mine does not spin up in idle mode but only kicks on when the gpu is stressed.  Have you seen this behavior, as I thought the fans should always be running?

Yup, I tried it and it works.  Both fans spin up at idle.

I have seen what you are talking about in terms of only one fan on at idle - not on this car - but another card.  Not sure why one would do it and not another.  But I guess as long as they are running when mining then it's all good.

[Cablez]

I hear you.  Thanks for the reply. 

[dropt]

Ok, I got it all put together and it works!     Here's the wiring:

I'd keep a damn close eye on that electrical tape.  It doesn't play well around constant heat.  If you feel so enclined: 

http://www.ebay.com/itm/2m-White-2mm-Tube-Sleeving-Heat-Shrink-Tubing-/160767521814?pt=LH_DefaultDomain_0&hash=item256e7db416#ht_2142wt_952

No sense in burning out the fan controller from a short.

[amazingrando]

I'd keep a damn close eye on that electrical tape.  It doesn't play well around constant heat.  If you feel so enclined: 

http://www.ebay.com/itm/2m-White-2mm-Tube-Sleeving-Heat-Shrink-Tubing-/160767521814?pt=LH_DefaultDomain_0&hash=item256e7db416#ht_2142wt_952

No sense in burning out the fan controller from a short.

Thanks for the link.  It came from the factory with a form of flexible fabric electrical tape.  I'll keep an eye on it and see how it runs.

[dropt]

I'd keep a damn close eye on that electrical tape.  It doesn't play well around constant heat.  If you feel so enclined: 

http://www.ebay.com/itm/2m-White-2mm-Tube-Sleeving-Heat-Shrink-Tubing-/160767521814?pt=LH_DefaultDomain_0&hash=item256e7db416#ht_2142wt_952

No sense in burning out the fan controller from a short.

Thanks for the link.  It came from the factory with a form of flexible fabric electrical tape.  I'll keep an eye on it and see how it runs.

Run of the mill black electrical tape goes tacky instead of sticky when it's been heated sufficiently.  Add some vibration and tape wrapped around onto itself it will loosen up/unravel.  I hear what you're saying about the fabric backed tape.  They must use a different adhesive, or possibly the fibre backing prevents it from loosing its grip.  Either way, would hate to see you loose a card in the event it goes awry.  You may end up just fine though.

[Cablez]

I changed the orientation of my GB5870 from the heatpipes at the highest point to the fans facing up and I have seen a decrease in temps of about 3 degrees.  Not huge but I'll take it.   

[amazingrando]

I changed the orientation of my GB5870 from the heatpipes at the highest point to the fans facing up and I have seen a decrease in temps of about 3 degrees.  Not huge but I'll take it.   

Did you also try fans facing down - the way it would be if it was in a computer case?  Curious to know how that performs

[Cablez]

Actually I didn't because I had put it into my inverted atx rig for the test. Door open and no extra or top fans so its real similar to my open frame rig.  With this setup I cannot do fans down though, sorry.

[pirateat40]

You're fine, looks good.