2 Replies Latest reply on Jun 30, 2016 7:20 PM by waltc

    RX480, Can you Crossfire an 480 8 gig model with a 480 4 gig model?

    brucer

      As the question asks...

      I know the memory on the 2 cards seem to be at different clock speeds from what I gather, but the memory isnt accessed on the 2nd gpu when in crossfire, so is this a viable option and a savings of $40 towards a crossfire setup and not losing any performance?  Just a thought..

        • Re: RX480, Can you Crossfire an 480 8 gig model with a 480 4 gig model?
          amdpete

          Both GPUs memory is used when in Crossfire, 4GB wouldn't get used though if you have one with more RAM than the other.  Each GPU needs a copy of the same data it needs to render which is why both lots of GPU memory is needed.  So if it were me I would get two of the same cards whichever way around you want to do it.  It would also be a bit more future proof to get 2x 8GB but only really if you are going to be using a high res display for the most part.  Games are only going to use more GPU RAM over time not less after all.

            • Re: RX480, Can you Crossfire an 480 8 gig model with a 480 4 gig model?
              waltc

              Well, it seems like if his 4GB GPU was "first" in the chain or pair for x-Fire, then what would be mirrored would be the 4GB card, which the 8GB card could of course handle with ease.  That should work, I'd think.

               

              Also, although I have yet to see a game with a *true* D3d12 engine supporting it (such an engine would require a d3d12-hardware card, too--as opposed to simply "supporting" a D3d12 card), d3d12 allows developers to actually use all the memory in a two-card xFire setup without mirroring--that is, a 4GB and 8GB card would have 12GB's actual VRAM available to the game! Two 8GB cards in xFire would have 16GBs of total VRAM game memory available--no mirroring, etc.  But as I say, no one has written a game engine that does that, yet...;)  It may be awhile before we see one, maybe, because it will require a brand-new engine and it will *require* a D3d12 hardware GPU.  Until then, though, mirroring, as you point out, is a requirement of current xFire-supporting/allowing game engines...

               

              If it is strictly a matter of moola...;)...then I would opt for the 8GB card first and then later buy another when I can afford it, so I'd agree that a matched pair is just a better choice.