Bitcoin Forum

Bitcoin => Mining support => Topic started by: erpbridge on April 13, 2013, 02:53:17 AM



Title: Dummy Plugs - Needed any more?
Post by: erpbridge on April 13, 2013, 02:53:17 AM
Silly question: Are dummy plugs required anymore for mining rigs? 

Have a 7950 on a Windows box, want to install a second 7950 once my 1x-16x cables come in from Cablesaurus. Have been reading conflicting reports as to if Dummy Plugs are needed or not. I don't want to have to worry about doing a monitor shuffle down in my basement when starting mining back up.

Thanks.


Title: Re: Dummy Plugs - Needed any more?
Post by: crazyates on April 13, 2013, 03:56:58 AM
With newer drivers? No.


Title: Re: Dummy Plugs - Needed any more?
Post by: c789 on April 13, 2013, 04:42:11 PM
I mine on Win7 and Xubuntu. With Win7, I don't need dummy plugs. But with Xubuntu, if I don't use a dummy plug, the system recognizes both of my GPUs but they each mine at half of the rate they're supposed to. If I use just 1 dummy plug, I get the full hash rate from both. (shrugs)  

So, you should be ok without one, especially on Windows. But if something is not right once you get everything up and running, you could always plug one in and see if it makes a difference or not. I used the DVI -> VGA adapter that came with my card and made a dummy plug with that and three 75 ohm 1/4 watt resistors, as described here: http://www.geeks3d.com/20091230/vga-hack-how-to-make-a-vga-dummy-plug/

You can get 10 of these resistors on eBay for $3.


Title: Re: Dummy Plugs - Needed any more?
Post by: os2sam on April 14, 2013, 12:39:01 PM
Like C8 said your not supposed to.  But when I don't use one on my 2nd GPU weird things happen, hashrate drops, card instability and such.  When I put a dummy plug on one card and the monitor or the other and extend the desktop everything is stable.  I'm using Win7 32bit.
Sam