Dual GPU one board 2GB of total RAM or still only 1GB?

Shinseina

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Apr 1, 2012
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I'm looking to upgrade my XFX HD 6870 2GB card with http://www.newegg.com/Product/Product.aspx?Item=N82E16814131446 in crossfire. It looks like this would be an ideal solution as it gives me 3 gpu's to get around micro-stuttering, while still giving awesome performance. I know that crossfiring a 1GB card with a 2GB card will result in a default 1GB of usable RAM thus rendering the 2GB card useless. I also know for a fact that both GPU's on powercolors card are 1GB of RAM each.

So here's my question:

Will I see only 1GB of usable RAM when crossfiring the XFX HD 6870 2GB with the PowerColor AX6870X2? Or does both GPU's being on one board somehow combine both GPU's RAM and make this card efficiently use 2GB or RAM?

I know that normally 2GB vs 1GB renders no change in performance, but I plan on doing eyefinity across 3 23" displays and therefore I feel like the extra RAM will be handy for this larger resolution.
 
Solution
kudos to lark for paying attention. 1+1+2= 1

I think "tri" cross fire is worth more headaches for not so great returns.

2 standard 2gig 6870's should run 3 monitors fine.

if you have micro stuttering how do you know it's the video cards problem ?

larkspur

Distinguished


You want the 2gb cards for eyefinity. Mixing even one 1gb card will limit the other two cards to using only 1gb each. So do your setup with 2gb cards for eyefinity. It'll be much better.
 

Shinseina

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Apr 1, 2012
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Well to be honest I do not know for sure that I am going to have micro stuttering, I have just been reading a lot of reviews and it's a problem a lot of people see with crossfire/sli setups.

Anyways you all answered my question, thanks for the quick replies!
 
It's 1+1+1=1

The 2 GB is Physically equipped with the card as the total amount, but in reality it's Dual GPUs connected internally with CF mode with 1 GB of VRAM each, so you'll end up having HD 6870 CFX (3-way CF).

And in theory, the third card doesn't add much power to the scaling of GPUs, there will be no microstuttering but the performance won't be high in eyefinity as the HD 6870 is not strong and the 1 GB of VRAM would bottleneck.

Better sell the current HD 6870 and grap 2 HD 7870s in CF.