1. Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

Crossfire Compatibility

Discussion in 'AMD / ATI' started by red99, May 15, 2011.

  1. red99 New Member

    Joined:
    Mar 25, 2011
    Messages:
    4 (0.00/day)
    Thanks Received:
    0
    In Crossfire: Do brands,model have to match to work? Can 1gb and a 2gb be linked if they have diff. manufacturers?:D Lastly: Does clock speed have to be identical out of the box if not OCing them?
     
  2. RejZoR

    RejZoR

    Joined:
    Oct 2, 2004
    Messages:
    4,777 (1.29/day)
    Thanks Received:
    1,003
    Location:
    Europe/Slovenia
    Only requirement is that you use the same class and same memory capacity.

    So for example 2x HD6870 with 1GB of memory. Or 2x HD6970 etc

    Last time i checked different clocks work together as well and brand itself doesn't mean anything.
     
  3. Crusader

    Crusader New Member

    Joined:
    Jan 6, 2009
    Messages:
    458 (0.21/day)
    Thanks Received:
    64
    Location:
    Victoria, Australia
    I believe, that if one card has 2GB and one only has 1GB, that only 1GB from both cards will be used. Same deal with clocks. Could be wrong, iunno.
     
  4. cadaveca

    cadaveca My name is Dave

    Joined:
    Apr 10, 2006
    Messages:
    14,098 (4.48/day)
    Thanks Received:
    7,279
    Location:
    Edmonton, Alberta
    Yes

    No, clocks are independant. Same with Shader count.
     
  5. AlienIsGOD

    AlienIsGOD

    Joined:
    Aug 9, 2008
    Messages:
    3,484 (1.52/day)
    Thanks Received:
    1,544
    as far as i kno Crusader u have it right. mem and clocks will go to lowest common value. brand/company do not make a difference nor does different models within the same class ie. 4850 + 4870 crossfire ( i have seen that here on TPU b4). I personally bought 2 Sapphire as to have minimal issues with Crossfire
     
    Crunching for Team TPU
  6. t_ski

    t_ski Former Staff

    Joined:
    Apr 11, 2006
    Messages:
    10,991 (3.49/day)
    Thanks Received:
    4,540
    If clocks are different, the lowest clock will be utilized. Example is if you have one 6990 and one 6970 for tri-fire, you will use the 6990 clocks. Brands do not need to match as I have done this for years. However, if they run at different clocks (one regular card, one "OC" edition), the lowest will be used.
     
    Crunching for Team TPU
  7. crazyeyesreaper

    crazyeyesreaper Chief Broken Rig

    Joined:
    Mar 25, 2009
    Messages:
    8,171 (3.95/day)
    Thanks Received:
    2,811
    Location:
    04578
    exactly

    6850 + 6870 works

    5850 + 5870

    5830 + 5870

    5850 + 5970

    5870 + 5970

    6950 + 6970

    6950 + 6990

    6970 + 6990

    essentiall family name is all that matters with xfire

    x8xx will work together
    x9xx will work together so on and so forth

    at least when it comes to modern gpus aka not sure on the 2000 or 3000 series but this applies to 4000 5000 and 6000 series cards
     
    AlienIsGOD says thanks.
  8. 2DividedbyZero New Member

    Joined:
    Aug 2, 2008
    Messages:
    780 (0.34/day)
    Thanks Received:
    202
    Location:
    in retarded hell
    gone are the days where the lowest clock will be utilised.

    the memory is critical and the "least" used by a particular card will be used by all:

    ex1, a 2gb card xfired with a 1gb card will use 1gb

    ex2, a 5850@725/1125 can be used with a 5870@850/1200 WITHOUT effecting clock speed
     
    AlienIsGOD says thanks.
  9. cadaveca

    cadaveca My name is Dave

    Joined:
    Apr 10, 2006
    Messages:
    14,098 (4.48/day)
    Thanks Received:
    7,279
    Location:
    Edmonton, Alberta
    No. Clocks are not part of it.


    Although, i think that they should be.


    CCC allows for independant clocking of each card, even.


    Only memory size, and use of the same base GPU matters.


    You can run 4870 with 4850, 4870 with 4890, 5870 with 5850 and 5830, as well as 5970, and 6950 with 6970 and 6990. NO CLOCKS/SHADER AMOUNTS WILL BE ADJUSTED.
     
    AlienIsGOD says thanks.
  10. Zubasa

    Zubasa

    Joined:
    Oct 1, 2006
    Messages:
    3,980 (1.34/day)
    Thanks Received:
    457
    Location:
    Hong Kong
    This.
    Only difference you will see is the faster card with have a slightly less load %.
    For example, a stock 5870 CF with a OCed 5870, the OCed card will be loading at 95% while the stock card will be at 99%.
     
  11. t_ski

    t_ski Former Staff

    Joined:
    Apr 11, 2006
    Messages:
    10,991 (3.49/day)
    Thanks Received:
    4,540
    Not according to this article:

    http://www.hardocp.com/article/2011/04/11/amd_radeon_69906970_crossfirex_trifire_review/

     
    Crunching for Team TPU
  12. cadaveca

    cadaveca My name is Dave

    Joined:
    Apr 10, 2006
    Messages:
    14,098 (4.48/day)
    Thanks Received:
    7,279
    Location:
    Edmonton, Alberta
    Not my fault Brent failed. :laugh:


    What can I say? He made a mistake? Because I know, for a fact, from doing it myself, you can adjust card clocks separately with that combo. I really make an effort of saying nothing unless I've tried it myself.
     
    Last edited: May 16, 2011
  13. t_ski

    t_ski Former Staff

    Joined:
    Apr 11, 2006
    Messages:
    10,991 (3.49/day)
    Thanks Received:
    4,540
    I never said you could not adjust the clocks separately. It just means that if you throw mixed carfs in there, that they should default to the lower speed. You're free to OC from there all you want.
     
    Crunching for Team TPU
  14. cadaveca

    cadaveca My name is Dave

    Joined:
    Apr 10, 2006
    Messages:
    14,098 (4.48/day)
    Thanks Received:
    7,279
    Location:
    Edmonton, Alberta
    Never seen it happen, myself. I can explain why it looked that way to brent, but he's wrong. Install the 6970 first, as I did, and something far different happens. I think maybe he ran two 6990's on that OS before the triple setup, although it could be possible that my differnt earlier config is truly what's the cause.

    And he did say syncronize, not actually drop clocks, which may kinda cover him there, as Zubasa states above.
     
    Last edited: May 16, 2011

Currently Active Users Viewing This Thread: 1 (0 members and 1 guest)

Share This Page