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SLI Vram Question

post #1 of 9
Thread Starter 
I know you only use one card's Vram, but there's another question regarding two different memory configurations.

Is it true that if you have a 1GB card and the same model but the second only has 512MB that you only use 512MB? This would make little to no sense as the second card should only bolster the first's fill rates. o_O

Can someone elaborate on this one?
     
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post #2 of 9
They are not actually sharing memory. They are alternating the frames they render. One card does the odd frames and the other does the evens. The 1GB card will drop to 512MB to keep pace with the other card. No reason to have the odd frames have more AA than the even ones.
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post #3 of 9
You can not SLI different memory cards, unlike CFX which can.

Also in CFX, the cards are going to the lowest common config, aka lowest card's core, memory size and memory speed.
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post #4 of 9
Thread Starter 
Quote:
Originally Posted by Defoler View Post
You can not SLI different memory cards, unlike CFX which can.

Also in CFX, the cards are going to the lowest common config, aka lowest card's core, memory size and memory speed.
No you can SLI different memory cards. I know from past experience.
     
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post #5 of 9
Any data is mirrored between cards.
Therefore, it would be impossible to mirror 1 GB worth of data onto a 512 MB card.
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post #6 of 9
Quote:
Originally Posted by beers View Post
Any data is mirrored between cards.
Therefore, it would be impossible to mirror 1 GB worth of data onto a 512 MB card.
So if two cards are at say 1000 core and ones at 950, all will run at 950?

Thanks, Sir Overkill.
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post #7 of 9
Thread Starter 
Quote:
Originally Posted by Sir Overkill View Post
So if two cards are at say 1000 core and ones at 950, all will run at 950?

Thanks, Sir Overkill.
Yes.

And thanks to the other guys who answered this question. Makes a bit more sense now. Though if one card is simply bolstering the other's fill rates, why would it matter if one card had half the Vram? Makes you wonder... >.<
     
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post #8 of 9
Quote:
Originally Posted by Imglidinhere View Post
Yes.

And thanks to the other guys who answered this question. Makes a bit more sense now. Though if one card is simply bolstering the other's fill rates, why would it matter if one card had half the Vram? Makes you wonder... >.<
...

The second card is _not_ just bolstering the first's fillrate. As someone said above, to render alternate frames, the same data needs to be in the memory of both GPUs, which means the bigger one can only have a maximum of 512MB of data.
post #9 of 9
Thread Starter 
Quote:
Originally Posted by jenesuispasbavard View Post
...

The second card is _not_ just bolstering the first's fillrate. As someone said above, to render alternate frames, the same data needs to be in the memory of both GPUs, which means the bigger one can only have a maximum of 512MB of data.
You don't see the usage of the other card's Vram though. See my point now? I heard everyone. It doesn't make sense how it works is what I'm saying.
     
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