11 Replies Latest reply on Jul 15, 2016 9:17 AM by ramchyld

    Three-way CrossFireX supported cards?


      Hi, I have another question regarding AMD GPUs, this time three-way Crossfire.


      Long story short, I want to use 3-way CFX while reusing the Phenom II x6 CPU of my existing rig- again to try to drag on until Zen comes out, wherein I'll start on a complete ground-up build. The intention is to use 3-way CFX as a standard, but to drop to normal two-card CFX with the third card dedicated to physics/OpenCL calculation on games that support such profile.


      I have chosen the Gigabyte 990FXA-UD5 R5 as my motherboard since it has the x16/x8/x8 PCIe configuration needed for three-way CFX.


      Herein lies the rub: I understand from AMD's website that not all graphics cards can do three-way CFX, especially the newer ones that don't use a CFX bridge? The site seems to indicate that only specific R9 cards, namely 280, 280X, 290, 290X, 295X2, 390, 390X, Fury and Nano cards, can scale beyond two cards. I also could not find anything concrete on the RX480 or Radeon Pro Duo regarding CFX.


      However some sites I've stumbled across seem to imply that it is possible to do three-way CFX on any Radeon cards that doesn't need a bridge?


      So, I would like to know, is it possible to three-way CFX any Radeon cards and not just those mentioned, especially if they do not need a bridge? Because I'd like to use three mainstream cards like R7 360s to do this.


      Thanks in advance.

        • Re: Three-way CrossFireX supported cards?

          So you are wanting to use three R7 360s instead of a single RX 480 why again? Even if you can achieve perfect linear scaling, the RX 480 is still more powerful, so you'd still have lower performance. Also you'd be spending more money, three R7 360s at $93 (the cheapest model on Newegg) come to $279 whereas custom RX 480 versions are expected to retail around the $250 mark. And finally, with 2GB RAM on a 360 vs 8GB on the RX 480, you're going to be highly hamstrung in any game at 1920x1080 or above.


          So do yourself a favor and wait for the custom RX 480s to release and grab one of those (July 22nd for the Sapphire Nitro RX 480), and take all misguided thoughts of a horrid three way low end card arrangement and throw them out the window.

            • Re: Three-way CrossFireX supported cards?

              I do want to go with the 480. Just a few problems preventing me from doing so.


              The 480 is incredibly rare over here. All the brick-and-mortar stores I've went to say that AMD Malaysia hasn't brought it in, and the one online store that have them are selling them at exorbitant prices. Can you imagine paying US$299 per card instead of the promised US$199? Sure, it's the 8GB version, but that's still a horrible mark-up from US$249. Adding salt to the wound is that Newegg folded their Malaysian operation two years ago and no longer ships here, allowing said online shop to technically monopolize sales and set their ridiculous prices.


              Additionally, I do intend to go with 480s (three of them) on my Zen build. This build is just meant to keep my already-7-year-old rig running a little longer until the much-delayed Zen CPU comes out (seriously, it's already past the middle of the year, and still nothing. Not even signs of AM4 motherboards. And to think that sites like WCCFTech claims that AM4 boards was to appear in the market in June alongside stopgap Bristol Ridge AM4 CPUs).


              And the intention, as mentioned, is to keep the compute work separate from the graphics work, ie dedicate one card to physics/OpenCL/DirectCompute calculation so that it doesn't interfere with the graphics rendering on the other card.


              To be honest, I wouldn't have considered this build at all and waited patiently until Zen comes out and more shops to carry the 480 had it wasn't for Grand Theft Auto V (which a friend bugged me into getting) and NVidia giving me hell on my current build (long story short, character striping glitch. Needs updated NVidia drivers, but the graphics drivers that fixes the issue isn't compatible with the 7 year old NForce 980a board I'm using. NVidia support told me to get a newer board, so that's what I am doing- I'm changing it to an AMD, and along with it I want to change the graphics cards to AMD as well).