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  • Youpala Level 1 (0 points)

    Hello all


    i wanted to give you my feedback about upgrading HD4850M to the HD6970M 2GB, that i've just do !!

    As as have readed before in this thread, some people hesitate to upgrading like this, and here my experience :


    My imac is : 27" i7 (860) late 2009 model version 11,1

    the card i bought : 0005113?pn=1&s=661-5969&per_page=30


    How to :

    1) open the imac, remove the panel take care cables .... as usual
    2) unscrew the end of the frame heatskin of graphic card (HD4850m)
    3) unscrew the 3 screws on
    the graphic card support to motherboard
    4) removing the probe T°C connector
    5) unplug short small movement the
    graphic card on its slot
    6) cut about 2 cm ² plastic where the larges cables are for the new
    heatskin of graphic card, HD6970m is a little more cumbersome (it's easy to compare both cards)

    7) replace the larges cables correctly
    8) positioning the graphic card and plug as the same as original step 3) and 2)
    9) don't forget to re-connect the
    probe T°C connector

    10) close the imac and go !


    Strated in Osx 10.6.8 (with lastet drivers for HD6970m) and it immediatly reconized on my desktop !

    Performances are about 2x than the HD 4850m under Bootcamp (windows 7 64bit, Catalyst 12.8 needed)


    The best of all is, the T°C is lower than the the old one and nice to be ovecloked via ATI overdrive utility

    Let you to try this, you will not be disappointed !!


    For french people (what i'm) you can order to very easy shipping to french without any Taxe ... just specify "Gift" .


    That all,  thanks to have read me with my very poor english


  • Braccobaldo Level 1 (0 points)

    Hi all,

    I performed my upgrade from a 4850 to 6970. No problems about heat fan and it appears working perfectly with OS but it seems there are some problems with games: happens that I have a good frame rate but if I chance my view of 180• I have a heavy drop of frames. Is it a bottleneck?

    Is there any utility or software that can check if everything is working properly?

    Thanks all

  • RyanAlan Level 1 (0 points)

    Braccobaldo, the slow down you're reporting is the system overheating!


    Run SMC fan control around 3000 rpm for the ODD fan, up the CPU and HDD if you want.

  • Teut Level 1 (0 points)

    Do you run bootcamp with games? If yes make sure you change the mouse driver, its known to drop frame rates.

  • Braccobaldo Level 1 (0 points)


    so is it a overheating problem? I haven't checked the temperature and fan speed, but I haven't heard any fan going faster. Overheating is a common problem or there is any problem with the heatsink that is not correctly asssembled with the video card? ?i'll install SMCfan and make some tests.


    no, I don't use bootcamp for gaming, but I hadn't update my OS, so today I update it from Snow Leopard to Lion, maybe there is a problem with old drivers in SL.

  • Youpala Level 1 (0 points)

    You're true RaynAlan , we need to rise up Fan ODD speed because of heating ...

    Gpu core t°C is lower than HD4850M due to 3 pipes vs 2, but  HD6970M dissipates quite more heat .


    Braccobaldo, if you will use Bootcamp, try GPU-Z , it's  good to check any t°C / speed of your HD6970M.

    Don't forget to install Catalyst 12.8 driver.


    I've played Crysis 2 during 3 hours => t°C not exeeded 78°c with ODD speed 2800 trs/min, but all the case of Imac was hotter than before (with HS4850M) .

  • Teut Level 1 (0 points)

    I don't have the problem regarding heat. If I play games the iMacs fans are fine to cool down the new card.


    Using bootcamp and CPU/GPU-Z doesn't work as the heat sensor of the mac is different - so don't be surprised if you get wron values.

  • Youpala Level 1 (0 points)

    Maybe you are right for Gpu-Z in Bootcamp,

    and I forgot to precise that i changed my main Hard drive (1To) to the SSD Samsung 830 - 256GB => that is why i had to managed Fan of my Imac via SmcFanControl .


    Today, the best solution i have to set Fan is  :

    1) Boot Osx and manage Fans (find best ratio nose / t°C)

    2) then reboot to Bootcamp while Imac keeps the settings before (Osx)

    3) playing (hard) and  happy ....


    if I had kept my HD, it worked well as you Teut !

  • Braccobaldo Level 1 (0 points)

    As soon as turned on which should be the temperature of the imac@6970 ? or the temperature and the fan with normal using (safari, mail, pages etc)?

    I ask this because considering I installed myself the heatsink above the video card maybe is not correctly placed.

  • majzoo Level 1 (0 points)

    i have read this tread and i find it really interesting. I also got a question.

    Is any of these upgrades possible to do in my Imac 21.5 model 10.1 I think its early 2009?

    Now i got the radeon hd 4670 card with 256 mb VRAM.

    It would be really nice to add some extra speed with an SSD and perhaps a better graphicscard.



  • John Davison Level 1 (0 points)

    So I'm replacing the video card in my late 2009 27", not for better performance, but because the original 4850 bit the dust.  I'm not a gamer, and I don't *think* I'm running any apps that take advantage of OpenCL.  I'm definitely not going to spend the cash for a 6970.  Will I notice a difference in desktop/2D performance if I drop down to a 256MB 4670?  Would I be better off with a 512MB 6750, or does anyone want to sell me their 4850 for cheap?

  • Teut Level 1 (0 points)

    As I replaced mine with the 6 series you can have it cheap. Problem is I would send it from Germany, maybe customs is a problem. Where are you located?

  • John Davison Level 1 (0 points)

    I'm in Vermont, USA.  Yeah, customs might delay things a bit longer than I would like.

  • BrandonFromTX Level 1 (10 points)

    Returning to the AirPlay topic for a moment:


    Us hack-graders are out of luck! The feature uses the Intel integrated graphics as the driver for AirPlay.

    The first gen i5 and i7 lacked this.

    Even my iMac 27" core i7 880 (pretty sure it's the only one on earth!) can't pull it off, and it's the fastest possible in the iMacs of yore.


    We did trick the software into displaying the option by some registry mods, but the results weren't there.

    We would only get black screens or white screens, which were apparently the software trying to switch to those Intel graphics.


    If anyone wants to pursue it further (perhaps by modding Mountain Lion's/AirPlay's registry?) I will happily share what progress my partner and I made.

    We did posture that maybe somehow spoofing a 2011 27"'s ID and imitate an "always use discrete - never use integrated" mode we could make it happen, but we couldn't find out how to spoof settings on spoofed models.


    Best of luck, hackers and modders.

  • BrandonFromTX Level 1 (10 points)

    Also, John Davidson:


    I will happily part with my 4850. I'm in Texas.

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