Crossfire and DVI dummy adaptor

[Teekay]

Hi Guys,

While putting together a rig using

MSi GD80 Mobo and 4x VTX 7970 just a little confused about the crossfire part, dont intened to use it for any gaming so aam i safe to assume that i dont need to plug in crossfire cables.

secondly do i need to plug in dummy the dummy dvi vga adaptors the ones with the 3 resistors in... or will the cards work without them.

[FalconFly]

For mining you don't need any of those, leave crossfire disabled, no DVI dummies needed.

The Software should then recognize all cards via OpenCL and crunch on.
Installing Dummy DVI plugs (to simulate attached monitor) would actually increase their power consumption without any benefit.

Just make sure your setup is cooled properly, 4 cards in a PC case would need quite a high-end Big Tower with lots of big fans. Otherwise, they won't live long.

[BitcoinDenvini]

You dont have to use crosfire bridge, dummy plug is also unnecesary.

[Gator-hex]

Yeah the two previous posters are correct.

If you did want to game you could using one card while the other three keep mining.

[Teekay]

Thanks guys as i was getting mixed signals from elsewhere and i noticed on some rigs people have got the dummy adapters that they made up with 3 150 ohm resistors in them and put them on the end of every graphics card..

[ineedit]

It is rig dependent, some do and some don't.

I have one rig that is completely headless, no dummy plugs, no main monitor but I have another that just has to have a dummy plug or monitor on the 1st PCI-e card or it just presents a black screen to all remote login software until one is there.

[HellDiverUK]

The DVI to VGA adapter that comes with the GPU usually works, too, rather than making your own dummy.

I have a DVI->VGA in my LTC mining rig, because VNC is a retard and won't work without it.

[Kluge]

You don't need three resistors, only one. (*IF* you need it at all)



68-75 ohm seems to be the agreed-upon "hasn't screwed something up, yet" range.

[FalconFly]

Hehe, I remember that picture from somewhere... The good ol' MacGyver fix

AFAIK, these dummy plugs (or workarounds) were needed in very early OpenCL or its infancy (ATI BrookGPU) times, as otherwise the Software usually didn't recognize more than 1 video card.
Luckily, these times are over.

[BrewCrewFan]

O wow no plug needed anymore??! I finally "invested" into some GPU cards from ATI after being stuck on nvidia for so long. First thing I did was went to radioshack and got me some resisters lol. I mean they are not expensive, but the cards that I got only got a total of 2x the converter plugs so I had to scramble to look for some spare ones I had saved.