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do both GPUs in CF have to be clocked exactly the same

post #1 of 12
Thread Starter 
old question, just want to clarify

I want to CF my 6950, and I will have 2 CF bridges so I guess I'll use both

Is there any benefit at all in games from running the cards at different core/mem speeds

or does CCC automatically

slow the faster core to match the other core
slow the faster mem to match the other mem


I got lucky with this sapphires OC potential, I guess another reason to get a TF III with great cooling is it should match the sapphires OC, since they are more likely to hit 1GHz from reviews I read
Edited by Mit Namso - 6/18/11 at 3:16am
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post #2 of 12
While I don't think it actually changes the settings in CCC I believe it will throttle down the faster card to the slower clock speeds.
    
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post #3 of 12
If you check GPU usage in Afterburner, & have as example 1 GPU at 900 mhz & it's brother at 1000 mhz? You will notice that (under conditions of 99% gpu usage is easiest way to check this) there will always be a 10% differentiation between usage. The same proportion as they are separated in terms of clock speeds. So you can run both at separate clocks, surely, but they will operate @ same practical capacity.
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post #4 of 12
Thread Starter 
that will be the 1 downside of using a TF III-not maxing it, no big deal, only $20-30 extra for the better cooling
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post #5 of 12
Quote:
Originally Posted by XXXfire View Post
If you check GPU usage in Afterburner, & have as example 1 GPU at 900 mhz & it's brother at 1000 mhz? You will notice that (under conditions of 99% gpu usage is easiest way to check this) there will always be a 10% differentiation between usage. The same proportion as they are separated in terms of clock speeds. So you can run both at separate clocks, surely, but they will operate @ same practical capacity.
^^^ This is accurate and not speculation. Because of the way crossfire divides tasks, in MOST cases this will occur --- you will be able to overclock them individually, but you will often see the performance of the lower card being the proverbial "bottle neck"

At least - thats been my experience AND what Ive heard from others. I treat it as fact, but if we could get a third confirmation, that would be swell~ ^_^
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post #6 of 12
Quote:
Originally Posted by Mit Namso View Post
old question, just want to clarify

I want to CF my 6950, and I will have 2 CF bridges so I guess I'll use both

Is there any benefit at all in games from running the cards at different core/mem speeds

or does CCC automatically

slow the faster core to match the other core
slow the faster mem to match the other mem


I got lucky with this sapphires OC potential, I guess another reason to get a TF III with great cooling is it should match the sapphires OC, since they are more likely to hit 1GHz from reviews I read
No & they will load balance accordingly, no probs.
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post #7 of 12
Any reason to use both CF bridges instead of one?
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post #8 of 12
Quote:
Originally Posted by Cpt.Jeff View Post
Any reason to use both CF bridges instead of one?
No.
    
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post #9 of 12
so the extra clock speed on one card won't increase performance at all?
post #10 of 12
@ OP

The faster card will down clock to the slower cards speed.

Kind of like if I get a 6970 and use bios 1 on my 6990. The 6970 will use my 6990 bios 1 clock speeds.
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