New Rig 2nd GPU Question

[The_JMiner]

I just set up my new rig running.

Currently using 2 Sapphire Radeon HD 6750s

I am probably going to switch the cards later.  My operating system recognizes the 2nd card but Catalyst does not,
was I supposed to buy the Crossfire bridge as well???

(First time setting up twin GPUs)

[gellimac]

you have to make a VGA Dummy to simulate a screen on the second card or crossfire them

[Jack of Diamonds]

you have to make a VGA Dummy to simulate a screen on the second card or crossfire them

No, Catalyst 11.7 preview removes the need for dummy plugs or using any sort of plugs/CF bridges

[gellimac]

yes but 11.7 is in beta and cause many crashes (feedback i read) I suppose he is with 11.6

[The_JMiner]

yes but 11.7 is in beta and cause many crashes (feedback i read) I suppose he is with 11.6

Actually I have 11.2 and it says I was up to date. Are 11.6  & .7 in beta?
Should I get 11.6?

[edit] I installed 11.6 and I guess I will look into this dummy plug thing.

[deslok]

You only need a single resistor not a full VGA dummy

[The_JMiner]

Got it guys! I just installed a 2nd input from my monitor to the video card. Appreciate the help!

[gellimac]

the 11.6 is stable

to make a "free" VGA Dummy plug :

Here is how to make up a dummy plug for your card in about 30 seconds.

All you need are three 68 ohm resistors from RadioShack. They come in packs of 5 for a buck.


You will need the DVI-VGA adapter that ships with every GFX card, the resistors and a clipper. You could use scissors or a nail clipper, the wire is soft.


Bend one leg of the resistor around till it is parallel to the other then clip off the long leg so it is the same length as the bent leg.


The wire is just the right gauge to slide into the VGA plus securely.


Push it home. Note you want to bridge the top three pins on the right with the pins directly below one-to-one.. Hold the plug so the wide part is up top.


Alternate the resistors so the leg of one is against the body of another to avoid shorting out the jumpers.

And that is all there is to it. Start Folding on your second GPU

From overclocker.net

[deslok]

i'm going to refer you to the complete thread
http://forum.bitcoin.org/index.php?topic=16816.0

[Jack of Diamonds]

yes but 11.7 is in beta and cause many crashes (feedback i read) I suppose he is with 11.6

I've run 11.7 on dozens of GPUs for many days now without any stability issues or fooling around with resistors or dummy plugs.

But if you want to take the hard route that's fine too, just saying dummy plugs are 100% useless now

[gellimac]

ok didn't know

to you know if we can bypass the gpu overclock limitation with 11.7?

Can i Reach 1000MHz/350MHz/1200mV with my 3 * Sapphire 5850 Xtreme?

[Jack of Diamonds]

It's card dependent, I have 1 5850 Xtreme that locks up at more than 880mhz regardless of voltage, then another that goes up to 960 @ 1.2V

[gellimac]

ok but for now i can reach 900MHz i want to reach more but can't because of bios limitation.

I want to know if (like with TRIXX) I can go over 900MHz?

You reach 960 MHz with a Sapphire 5850 Xtreme?

[Jack of Diamonds]

You can go over the limit by just modding the config file in Afterburner.

But voltage can be only modded by Trixx