Author

Topic: 2 Ati cards (Read 2286 times)

hero member
Activity: 846
Merit: 1000
The One and Only
May 15, 2011, 12:22:15 PM
#9
The crossfire bridge can make windows see both cards without the use of dummy plugs. so If you've already got the crossfire bridge, use that.
newbie
Activity: 28
Merit: 0
May 15, 2011, 11:43:35 AM
#8
I can confirm that CrossFire affected mining speed on my 2x5870 rig. With CF bridges installed and CF enabled hashing speeds used to vary wildly between the two cards. Now I run with CF disabled and CF bridges removed but had to connect both cards to a KVM switch since I'm too lazy to go to the store and buy 6 resistors. Hashing speed is now constant and equal on both cards. I mine with Phoenix with phatk kernel and both 5870's run at 935/320.

One side note: CPU usage is at 100% under Windows, no matter if CF is on or off.
member
Activity: 84
Merit: 10
The Premier Digital Asset Management Ecosystem
May 15, 2011, 11:23:29 AM
#7
interesting, can anyone confirm/deny?
full member
Activity: 120
Merit: 100
May 15, 2011, 07:39:10 AM
#6
Not tested personally, but others state that Crossfire reduces the MH/s when compared to individual cards.
member
Activity: 84
Merit: 10
The Premier Digital Asset Management Ecosystem
May 14, 2011, 09:09:16 PM
#5
I thought all ATI cards come with a bridge... mine did anyway, so I should just use the bridge then?
sr. member
Activity: 504
Merit: 252
Elder Crypto God
May 14, 2011, 08:07:55 PM
#4
ok... but will crossfire increase or reduce mining speed compared to not using crossfire? or is there no difference? In which case is there any reason for me to use or not use crossfire...

There's no difference. The only difference is in the cost between the dummy plugs and the crossfire bridge.
member
Activity: 84
Merit: 10
The Premier Digital Asset Management Ecosystem
May 14, 2011, 08:03:39 PM
#3
ok... but will crossfire increase or reduce mining speed compared to not using crossfire? or is there no difference? In which case is there any reason for me to use or not use crossfire...
full member
Activity: 120
Merit: 100
May 14, 2011, 06:04:38 PM
#2
If im mining with 2 ati cards, do I put on the crossfire bridge between the two cards, and do I enable crossfire? Or just run the two cards as separate workers?

6 million posts already talking about this, but I'll answer it anyway and kindly request that you use the search function next time.

If you use Linux you don't need to Crossfire and the OS will see and use both cards.

If you use Windows you don't need to use Crossfire, but Windows won't see the second card unless it thinks there is a monitor on it. This can be spoofed using a VGA dummy plug. http://www.geeks3d.com/20091230/vga-hack-how-to-make-a-vga-dummy-plug/

I have 3 ATI cards all running on Windows without Crossfire.
member
Activity: 84
Merit: 10
The Premier Digital Asset Management Ecosystem
May 14, 2011, 05:34:10 PM
#1
If im mining with 2 ati cards, do I put on the crossfire bridge between the two cards, and do I enable crossfire? Or just run the two cards as separate workers?
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