eGPU or Build A Pc

Discussion in 'iMac' started by AlexxRyzhkov, Jan 15, 2015.

  1. AlexxRyzhkov macrumors regular

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    May 17, 2014
    #1
    So a friend of mine upgraded his Pc rig and gave me some of his old stuff. I got an AMD Radeon HD 7870, a Fractal Core case, an EVGA 500w PSU, a Gigabyte motherboard for LGA1155 (so Sandy and Ivy bridge CPUs) and a monitor. All I need is a CPU and some ram and a hard drive. The cost of a used i5-3570k, 8gb of ram, and a hard drive adds up to about $300

    Then I was thinking, I have 2013 iMac 21.5" (i5, 8gb, GT 750m), is it possible to get a thunderbolt adapter and just use the 7870 with the iMac? I'm gonna be running on windows 8.1.

    Also could I use the internal iMac display?
     
  2. h9826790 macrumors 604

    h9826790

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    #2
    Making the eGPU work flawlessly with your iMac most likely will cost you more than $300.
     
  3. thundersteele macrumors 68030

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    Switzerland
    #3
    You can use the iMac as monitor AFAIK. Getting a thunderbolt enclosure + cable for the GPU might be more expensive than completing what you have to a full PC.
     
  4. h9826790 macrumors 604

    h9826790

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    #4
    I think the Thunderbolt iMac can be a display for other Mac with Thunderbolt, but not for other PC.
     
  5. AlexxRyzhkov thread starter macrumors regular

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    May 17, 2014
    #5
    The thunderbolt dock I was looking at is the AkiTio Thunder2 which only costs $220.
     
  6. InfoTime macrumors 6502

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    #6
    I think it can. But I believe you'd use a DisplayPort connection from a PC. I've been doing that for about three years with my 2009 27" iMac. I have a Windows PC and when I play games I switch my iMac's screen to the Windows PC.

    I know it's slightly different on newer iMacs with Thunderbolt. But AFAIK the only iMac that doesn't support Target Display Mode is the new Retina iMac.
     
  7. h9826790, Jan 15, 2015
    Last edited: Jan 15, 2015

    h9826790 macrumors 604

    h9826790

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    #7
    The 2009 model is different, and the latest iMac that can be the Target Display for other PC is the 2010 iMac. AFAIK, the rule was changed when Thunderbolt introduced.The following is quoted from Apple webpage.

    "Support for Target Display Mode via the Thunderbolt port using a Thunderbolt to Thunderbolt cable (sold separately)"

    I didn't own this iMac, but other members' posts also show that it only works with Thunderbolt now. I wish I am wrong, but still no successful case to show that a Thunderbolt iMac can be a Display for other PC yet.

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    External PSU? Cables? Do you know how to flash the card? $220 all included?

    Some evidence shows that may be only a card with Mac EFI ROM can work as eGPU at this moment.

    Of course you can try, but I can tell you that's not gonna to be an easy task. Even though an expert may get into trouble when try to make an eGPU function normally on a Mac.
     
  8. AlexxRyzhkov thread starter macrumors regular

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    May 17, 2014
    #8
    I have an external PSU.
    I was reading a guide on someone who did this on a 2012 Mac Mini, and he said all you need was the AkiTio Thunder 2 ($220), an external PSU (I have one), and a thunderbolt cable ($30).
     
  9. UniDoubleU macrumors regular

    UniDoubleU

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    Thailand
    #9
    The thing is it's easier for a Mac without a display to use eGPU solutions. You lose some more processing power trying to display to internal GPU plus it doesn't work in all configurations.
     
  10. yjchua95 macrumors 604

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    #10
    I've no experience regarding AMD Radeon cards, but I've a Sonnet IIID + Corsair RM450 PSU + GTX 780 Ti hooked up to my 15" rMBP, and it runs plug and play in Windows (UEFI).

    Performance is about 85-90% of its full performance.
     
  11. definitive macrumors 68000

    definitive

    Joined:
    Aug 4, 2008
    #11
    could probably get a cpu + ram, and make a hackintosh out of it, though i'm not sure if the gpu is compatible. if not, you could always sell it, and buy something that does work, like a 650ti.
     
  12. jblagden macrumors 65816

    jblagden

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    Aug 16, 2013
    #12
    In term of performance, I would go with a Hackintosh. But due to cost, I went with an eGPU. The only issue with an eGPU is that the data has to be compressed on the Thunderbolt cable, which requires a significant amount of processor power. Though, at High graphics settings in StarCraft II, my GT 740 eGPU still manages to keep my MacBook Pro’s CPU 10 degrees cooler. I can go up to Ultra graphics, but the CPU temperature fluctuates between 93˚C and 96˚C.
     

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