Does anyone have 1st hand experience in crossfiring a 58xx card with a 69xx?

[kokojie]

I have a Radeon 6970 and I'm considering if I could crossfire it with a Radeon 5830? is it possible?

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[DeaDTerra]

From what I have heard you can not crossfire cards that are not the same model.
//DeaDTerra

[Olly_K]

as above, you can't.

But, you don't need to for mining

[KoKos]

You have to have the same GPU to crossfire

you have 6970>Cayman and 5830>Cypress

i.e. you could do it with a 6950 if you had one, but it would be like having 2x 6950 though

[grue]

just don't as it hinders performance.

[cyberhelix]

Amen

[Saturn7]

Crossfire will only double the speed of your slowest card and only If they are the same family (ex. 5850 and a 5870)
Plus when in crossfire mode, work gets sent to the 2nd GPU via the 1st GPU which is the cause of the bottleneck.

Crossfire is a real bad idea for mining.
You're better off mining on each card separately, especially if you have different GPU's

[rjk]

Crossfire will only double the speed of your slowest card and only If they are the same family (ex. 5850 and a 5870)
Plus when in crossfire mode, work gets sent to the 2nd GPU via the 1st GPU which is the cause of the bottleneck.

Crossfire is a real bad idea for mining.
You're better off mining on each card separately, especially if you have different GPU's

While this may apply to some games and things, I'm fairly sure it doesn't apply in the same manner to bitcoin mining. Bitcoin mining uses special kernels that are executed on each GPU regardless of whether Crossfire is enabled or not. From my experience, Crossfire causes neither a loss nor a gain in speed, but it does result in much higher CPU usage when enabled, which makes it a power hog.

[beaups]

I run a 5830 and a 6970 in one of my miners.  Don't crossfire them (you can't), just plug them in and launch cgminer.  It works fine, they both perform as expected.

[ssateneth]

You cannot crossfire a 5xxx with a 6xxx. It is impossible. You can crossfire a 5xxx to a 5xxx and a 6xxx to a 6xxx though, but your speed will be limited to your slowest card times the number of cards in crossfire.