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Crossfire Beginner... Tips Pls ;O)

Discussion in 'AMD / ATI' started by jonathan1107, Apr 28, 2011.

  1. jonathan1107

    jonathan1107

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    Hey guys, I'm getting my second radeon 6950 tomorrow and I am looking for some tips on how to get my system ready... and I also have a few technical questions.

    Alright here are my questions:

    1. Do I need to uninstall the drivers from my currently installed Radeon 6950 before adding the new one and booting the PC??
    2. My current Radeon 6950 has unlocked shaders... must I undo my unlock before adding the other one and unlocking it's shaders??
    3. My PSU supplies 1250w... is that enough for the 2 cards and my Rig (see my system specs for more details) ??
    4. I've heard that in the past, it was necessary to have a special DVI cable to connect the 2 video cards together to send a stronger signal to the monitor... Nowadays it seems we don't need this anymore... but does this mean we lose bandwith??
    5. I hear that Crossfire can bring the Scaling up to 2x with 2x Radeon 6950... But I also hear that Crossfire performs differently with different games... appearantly sometimes crossfire will perform even worse than a Single Card... Is this true?
    6. My current Mobo has two 16x PCI-e slots but they become two 8x when in Crossfire... How much of a performance Decrease does this represent?
      [*]I also hear that it's important to have "Crossfire certified RAM and a Crossfire Certified PSU"... is that true and if so... why?
    7. Do you have any other reccommendations for me???
     
  2. erocker

    erocker Super Moderator Staff Member

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    1. Yes
    2. Or just unlock your new card with just that card installed first. Drivers should be uninstalled for that process anyways
    3. Way more than enough (check my specs)
    4. No, that was an old adaptation of CrossFire that is no longer used. Use the two flexible bridges to connect your cards together
    5. Maybe? Use it and find out.
    6. Check W1zzards reviews on the subject. The answer is pretty much a no.
    7. Marketing BS.
    8. You're covering your bases. Make sure that when you are installing your CrossFire cards that all previous drivers are thuroughly uninstalled. Have both cards installed CF bridges on and install your drivers.
     
    Last edited: Apr 29, 2011
  3. entropy13

    entropy13

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    Make sure your case have good airflow too (as I see it it's only your CPU that is watercooled) so as not to starve one of the cards of air.
     
  4. jonathan1107

    jonathan1107

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  5. entropy13

    entropy13

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    jonathan1107 says thanks.
  6. jonathan1107

    jonathan1107

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    Thx a lot, this gave me great answers about the PCI 16x to 8x performance information...

    By chance, anyone know where I could find a CrossFire review of 2x Radeon 6950 (with unlocked shaders)

    Oh and ONE VERY IMPORTANT QUESTION for yall`

    Should I flash to 6970 bios or just unlock shaders?

    I've heard ALL SORTS of things about Flashing the Radeon 6950 to 6970... As for myself, I have tried it for maybe a month with my actual Radeon 6950... And it did yield a bit of an increase performancewise in certain games... (I remember I had a little bit better FPS in Crysis than right now)... But I decided to revert to the 6950 Bios with unlocked shaders for safety issues...

    I've heard that the memory timings are different on the 6950 bios, and that the electrical connectors (2x6pin vs 1x6 + 1x8 pin) can cause issues... I haven't experienced severe issues while flashed @ 6970 bios except for maybe the heat... and the fact that some games didn't seem to benefit the higher clock speeds and sometimes it would even be glitchy (I guess it's due to the different memory timings...)

    Also I constantly hear how Nvidia cards are better because they offer more Overclocking headroom, and some of their software is opensource and so fourth... But if I am just a beginner in overclocking video cards and people here are experts... How come no one has found a way to build a "Modded Bios of the 6950" that includes unlocked shaders with the CORRECT memory timings, and extend voltage limit to higher numbers, and unlock higher clocks on the card?

    I've heard that this could be done with software like RBE...

    Let me know what you think...
     
  7. silkstone

    silkstone

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    just unlock the shaders, modify the existing bios, there is an app out there somewhere, to minimize any risk
     
  8. random

    random

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    To answer question 5. Yes, some games don't work too well with crossfire although with newer games in the market the issues continue to lessen. To prepare yourself for any scaling issues I suggest you download a program called "Radeon Pro" It'll help you setup crossfire profiles for those games that just don't have their own coding done right to support it.

    Radeon Pro has so far helped me get rid of flickering in Crysis 2 and stuttering in Assassin's Creed Brotherhood.
     
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  9. jonathan1107

    jonathan1107

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    Thanks, that's some really good tips... A bit more specific than this: "just unlock the shaders, modify the existing bios"...

    I know how to unlock shaders... but I have no clue what this guy means by "modify existing bios"... That could mean anything from flashing it to 6970 to editing a completly new bios... and "there is SOME app out there"

    Wow, that doesn't help... please be more specific
     
  10. random

    random

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    In regards to unlocking your 6950, I personally would highly recommend to only unlock the shaders. Completely flashing it to a 6970 has long term implications a good example is the long term damage it will do to the memory, I've experienced this on my reference models and I got random minor artifacts even at stable clocks and there have been a few reports of people's cards dying overtime. I suggest to play it safe and just do shader unlock then overclock your card to 6970 speeds as it would be the same end result but under safer conditions.

    Look at Post #5 for the shader unlock only file.
    http://www.techpowerup.com/forums/showthread.php?t=141475
     
  11. jonathan1107

    jonathan1107

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    Anyone know where I could find 6950 unlocked vs 6950 "not unlocked" benchmarks???
     
  12. Wrigleyvillain

    Wrigleyvillain PTFO or GTFO

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    Uh wouldn't that be a simple "6950 vs 6970" comparison?
     
  13. jonathan1107

    jonathan1107

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    uhhhhhh No it wouldn't be because both cards don't operate at the same Clocks and they don't have the same memory timings and the like...

    So, there should be a considerable difference between an unlocked radeon 6950 with unlocked shaders only and an unlocked radeon 6950 with the 6970 bios...

    Even an unlocked radeon 6950 with the 6970 bios wouldn't perform as well as a 6970... because even thought the clocks and the memory timings would be the same... the power connectors aren't the same (which results in a lesser feed of power to the card/second) and the vram isn't the same on a 6950 which would probably cause artifacts...
     
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  14. jonathan1107

    jonathan1107

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    so YES, I would still like to see some benchmarks of unlocked radeon 6950 somewhere out there...

    Nevertheless, I will be posting 2xradeon 6950 crossfire benchmarks when I get my 2nd card setup later this week...
     
  15. cadaveca

    cadaveca My name is Dave

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    :toast:
     
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  16. Wrigleyvillain

    Wrigleyvillain PTFO or GTFO

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    Dave is right; you should not have to uninstall drivers/reinstall drivers. You can just put in the second card and power up and it should see it and add to device manager and then CCC starts up and shows you Enable CrossfireX checked. But to help ensure the smoothest, trouble-free setup of both cards in your system you should probably take erocker's advice and do so. Just like you can also simply install new Catalyst releases over old with no rebooting (the installer actually does some uninstall as well; it's not fully an "over the top" dump) but that doesn't always go smoothly for everyone either, ya know?

    Driver Sweepers and such really not necessary anymore but when in doubt or to be absolutely safe, uninstalling and rebooting first is still a good rule of thumb.

    And I thought the 16x16 vs 8x8 diff was actual-more like 1 to 2%-but it's totally nominal and irrelevant in real world usage. Going for a WR? Then you probably want full 16x... :)
     
    Last edited: Apr 28, 2011
  17. jonathan1107

    jonathan1107

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    Thank you Cadaveca... I'm glad I can pop in the new card without having to mess with the previous drivers...

    What happens if ... say I wanna update my current CCC which is 11.2 to 11.4? Can I just install 11.4 and it will be applied to both cards...? Or I have to do something special?
     
  18. Wrigleyvillain

    Wrigleyvillain PTFO or GTFO

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    No, driver updates are the same as before. Nothing really changes outwardly...

    As you are running 11.2 now I would definitely take this opportunity to do a clean install of 11.4 once both cards are in the machine. But, again, you should just be able to install the second card and then install 11.4 over the top of 11.2 (or just stay on 11.2 if you so chose for whatever reason) and it should all work just fine. Operative word is should, of course.
     
  19. cadaveca

    cadaveca My name is Dave

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    Yep, install second card, alone, mod, remove and put both cards in, with original card in top slot.

    boot into windows, let windows isntall driver; when it's done, reboot.

    once back at desktop, confirm Crossfire is active in CCC, close CCC window, install 11.4 without removing 11.2.

    reboot after it's done, upon boot, check CCC for crossfire enabled. run 3D app to confirm, too.


    Profit.
     
  20. erocker

    erocker Super Moderator Staff Member

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    Sure, but half the time it's not going to work properly so might as well do it anyways.
     
  21. cadaveca

    cadaveca My name is Dave

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    Yeah, sometimes, but it kinda sucks, and is not caused by the ATI drivers directly. Problems are the result of other software tools that interact with ATI drivers, more often than not. As directed by Terry Makedon when he was in charge of Catalyst development, driver removal prior to "upgrade" to new version is NOT recommended.

    however, he is not in charge any more, and has moved on to Fusion, so this might have changed. I'll ask for DIRECT confirmation of how this shoudl be done.
     
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  22. erocker

    erocker Super Moderator Staff Member

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    Well, Terry is absolutely 100% incorrect. I really don't care about what some AMD employee says about it. I do what works from experience. Besides most people should know that anyone involved with AMD driver development should probablly not take their advice anyways.

    *Let's be honest here, if AMD drivers worked like they're supposed to would we even be having this conversation? :laugh:
     
  23. cadaveca

    cadaveca My name is Dave

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    That's fine, just posting the source of my info and directions.

    And yes, I consider that you swapping between GPU makers on the same OS install leads to situations they have never experienced. But I have found, more often than not, the problems are not drivers themselves, but other things, like afterburner, or MS redist C++.

    See, if you remove drivers, but not these tools, many registry entries are left behind, so simple removal of drivers only is just not the way to go...you need to remove far more if you are going to take that route. Uninstallation of drivers needs to include removal of all other software that uses the driver, and the removal of these apps must be done FIRST. Many users do not do this, and then many run into problems...so even driver removal has it's share of issues as well, that can be avoided, by simply installing over top of the old ones.
     
  24. Wrigleyvillain

    Wrigleyvillain PTFO or GTFO

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    Exactly what I was trying to say, especially considering he is still at 11.2.

    And yeah if you have Afterburner or Trixx or RadeonPro or any of those utils installed then remove them before you do anything else.
     
  25. jonathan1107

    jonathan1107

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    do I need ccc drivers installed to use ATIflash (to unlock shaders)... I just uninstalled 11.2...
     

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