That RX xfire is confusing.

Lena__

Honorable
Jan 27, 2016
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Hello!
Have a question on multigpu. Crossfire has less restriction then SLI => seems harder.
To make things even harder, take rx *80 8gb and rx *70 4gb
I understand that it's 4gb ram now. And the *80 supposed to clock at *70 core&mem speed. What else is "downrated"?
And does it matter which card is in 1st pcie slot to be GPU0?

Like, is stronger videocard just use half of its vram? Or is it more like two gpu on same pcb?

p.s. no, i'm not "getting any ideas" :3
 
Solution
If you have two different cards say a 570 and 580 in crossfire, it will revert to the lowest common denominator. So if you had a 580 8gb and a 570 4gb in corssfire, you would essentially have two 570 4gb's in corssfire. Everything that makes the 580 more powerful than a 570 will be downgraded to 570 levels.

Dunlop0078

Titan
Ambassador
If you have two different cards say a 570 and 580 in crossfire, it will revert to the lowest common denominator. So if you had a 580 8gb and a 570 4gb in corssfire, you would essentially have two 570 4gb's in corssfire. Everything that makes the 580 more powerful than a 570 will be downgraded to 570 levels.
 
Solution


And for that reason I'd probably run a single 580 OR get dual 580's. Instead with a mix you're getting dual 570's.