Zalman VF-900's on a 4850 x2

[drugfreeboy]

Hey guys,

I bought a pair of these VF900's to quiet the jet engine that is the 4850 x2's cooling system, which is working out so far, and keeping temps manageable, but I have one beef that I think I can fix. I just want a second opinion.

The VF-900's use 3 pin fan connections that come with little crappy black boxes with knobs to manually adjust the fan speed, however, I've been spoiled with fans that connect directly to the video card and are automatically controlled by the catalyst software.

So my thought is to splice the connections and plug the new coolers into the video card


If I understand correctly, on a 3 pin fan one wire is the voltage (5v?) another is the fan speed, and a third is a grounding wire.

The cooling blocks that came with the video card use 2 pin connections, presumably one being voltage and the other, a grounding wire.


First, can I even do this?
Will the possibility of mixed voltages fry out the fans? Or not feed them enough power?
Can I make do without a ground wire?

it would be nice to have the gpu fans plug into the card itself instead of having a tangle of wires trying to find a spot on the motherboard to plug in (I dont have a spare one for the fan in my side panel at the moment) and have a ribbon of cables running out so I can turn these fans up every time I get into a game


Thanks in advance for any input
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[Conumdrum]

Well your problem is the fans need to send back RPM to the GPU so the GPU can adjust speeds. And yea you can use just the two wires, the black and red. Black is grnd, red is 12vdc. The GPU probably will run the two fans fine, I bet it's just by voltage and it doesn't monitor RMP of the GPU. Put the fans in parellel wiring and don't use the rpm wire.

You'll probably have to mess with the auto fan control to get it the way you want.

I'd google around a bit first to see what others have done.

You could always just get this.
http://www.jab-tech.com/Sunbeam-5-1-4-Rheobus-Kit-BLACK-pr-2530.html

 

[drugfreeboy]

Oh, I see. well thanks! that helps a lot

 

[drugfreeboy]

If anyone has the same issue as me, I was able to achieve success, however it required getting my hands a little bit dirty. The video card would not send enough voltage to keep the fans spinning. Enabling manual fan control, I was able to keep it spinning at a locked speed if I turned it up high enough, but I was concerned about the time it would take to get the CCC running and locking the fan at an appropriate speed should I...say... decide to reinstall windows.

I ended up flashing the video card's bios after editing it with Radeon BIOS Editor. By setting the fan to at least 25% at all times (still dead silent for the zalmans) I was able to make sure enough juice got to the fans to keep them going. (it seemed that if the temperatures got too low and the fans decided to slow down more, eventually they would stop, and there just seemed to be no way to get them to start up again)

I dunno a lot about this stuff, so this might not have been the best approach, but I know a lot of people put this cooler on the 4850x2 and at least a few might try this.