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Crossfire Question

post #1 of 10
Thread Starter 
I was just screwing around with my Crossfire configurations, and I was curious:

Is it better to have two GPU's running at 16x/4x or 8x/8x?

Both are in PCI-e 2.0 according to GPU-z. I'm trying to figure out if it's better to have those extra lanes, or if it's more stable/optimized using a balanced 8x/8x?
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post #2 of 10
You want them at 16x ITs more bandwith, not like you could use it all with the current hardware but PCIE 2.0 is showing more of an advantage now days!

8+8 =16 and 16+4=20

I dont know if that works out. But more lanes
    
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post #3 of 10
Quote:
Originally Posted by oOSauerKrautOo View Post
I was just screwing around with my Crossfire configurations, and I was curious:

Is it better to have two GPU's running at 16x/4x or 8x/8x?

Both are in PCI-e 2.0 according to GPU-z. I'm trying to figure out if it's better to have those extra lanes, or if it's more stable/optimized using a balanced 8x/8x?
Run 3dmark05/06 in each configuration and see which does better, then come back here and let us know.
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post #4 of 10
Quote:
Originally Posted by BlackOmega View Post
Run 3dmark05/06 in each configuration and see which does better, then come back here and let us know.
Superb Idea! +1
    
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post #5 of 10
Thread Starter 
Well naturally I want them at that, but my MOBO only supports 16x/4x or 8x/8x or 3 GPUs at 8x/4x/8x). I was just wondering if one or the other is better (16x/4x or 8x/8x) performance/reliability wise.
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post #6 of 10
Thread Starter 
Well I think I just figured it out...

I had a 1500 point boost in 3Dmark06 using 8x/8x vs. 16x/4x
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post #7 of 10
Quote:
Originally Posted by cyberboy View Post
superb idea! +1
Thanx
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post #8 of 10
That significant? It dont seem lagit to me. I dont see that big of a dfference. But glad you figured it out quick
    
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post #9 of 10
8x-8x will be better since the 4x gpu will be severely bottle necked.
Is it in yet?
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Is it in yet?
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post #10 of 10
Thread Starter 
Yeah I'm guessing the 4x card was bottlenecking. Also, I just noticed that in 4x mode the 2nd card had a lower GPU clock...MOBO must automatically turn it down. I'm guessing the 16x card wasn't utilizing all of the lanes (since it's 32x in 2.0 mode) and so it couldn't make up for the slower 2nd card even if it wanted to.

In 8x (16x in 2.0 mode) both cards are running at the same rates and there doesn't appear to be any significant bottlenecking. Obviously the cards don't utilize more than 16 lanes. Interesting, because I would've called the 16x/4x to be better!

I'd post the 3DM06 scores but I'm using my laptop to type this! If I get bored I'll do some copy/pasting later
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