Discrete Graphics cards in Mac Mini?

Discussion in 'Mac mini' started by toru173, Apr 16, 2007.

  1. macrumors regular

    Joined:
    Apr 5, 2007
    #1
    A thought struck me just recently - why can't we have discrete graphics inside the mac mini? Two reasons. There isn't any space, and there's no way to connect it. To the first we could always mount the card outside the enclosure - I'm sure many of us here are able and willing to sacrifice the time needed to make that look pretty (or even the good looks) in order to get some better frame rates.

    The second is more difficult to deal with. With a lot of thinking, though, I realised that the Airport card has to have an expansion bus of some sort. I had a look at pictures of the mini nude (here, labled "J") I recognised it as a mini PCI-e port. This is basically a PCI-e x1 port plus a usb port. Checking out the manufacturer's details for the 802.11n airport module (an Atheros card) confirmed this.

    I went and checked out one of my favourite sites for bus adapters, http://www.adexelec.com/ and I found this:

    [​IMG]

    This means that any PCI-e x1 card can be plugged into a mini PCI-e socket. With
    this
    , also from them, one could conceivably use any graphics card on the market today.

    Mechanically, they are now compatible. This article shows that it would also be electrically compatible, so long as the mechanical adapter would be able to supply sufficient power. Software? I don't know, but I'm quite sure that it would work under windows. Perhaps if the mac-specific cards were used, they would also be recognized by the mini?

    I don't have a mini nor do I have the funds to try this out. I'm almost positive that it would work, but I don't know how much of a performance gain you would actually see. Certainly any of the hardware accelerated features of the card would be demonstrated, but would one be better off just using the integrated graphics?

    At the very least, though, this would be an interesting hack. I hope someone tries it out ^_^

    [size=+2]EDIT: Expansion cards work in the Mac Mini - Graphics cards can't be far behind! See this post.[/size] - How do I change the title of a thread to reflect this?
     
  2. macrumors 68000

    flyinmac

    Joined:
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    #2
    An interesting post.

    I do imagine that drivers and support in OS X would be the primary issue though. Of course, someone could find a way around that I'm sure. It's just a matter of whether or not anyone would write such a driver.
     
  3. Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #3
    Any semi-reasonable graphics card will be massively slowed down by running on a single lane PCI-e bus. Current top of the range cards are noticeably slower when running on a 8x instead of 16x bus.
     
  4. macrumors member

    Joined:
    May 16, 2006
    #4
    Yes, but the question is how it will do compared to the GMA950. My guess? Way better =)
     
  5. thread starter macrumors regular

    Joined:
    Apr 5, 2007
    #5
    I addressed both points when I wrote the post.

    To the question of OSX drivers - The device should be recognised, unless apple has specifically limited the mini PCI-e socket to only respond to a specific hardware device ID, which I find highly unlikely. If this were the case apple would be restricted to only one model of Airport card. This article indicates that this may not be the case, as they were able to use a MacPro wifi card in the mini. This doesn't mean Apple hasn't restricted the port to a specific device type, but I don't see why they would. They gain nothing from it.

    If the device is recognised, you then need drivers - as flyinmac pointed out. This is why I recommended testing it in windows. Although cringeworthy, one of window's strong points is it's device support. This would enable us to test, at the very least, that the card was recognised and indeed capable of outputting a signal. The next step would be to either try a mac - specific card, or to write drivers (or even flash the card) to be supported under OSX. As naughty as they are, the OSX86 people have done a fair bit of work on the driver front.

    The second point, brought up by robbieduncan - yes, I am aware that modern video cards are severely hobbled when run at reduced bus bandwidth. I don't know how the performance would compare to the GMA950, but I would be prepared to try it at reduced performance for a few reasons. Firstly, discrete graphics cards can support HDMI, HDCP and dual-link DVI, three things that are missing on the mini that would be nice for a media center. Secondly, a lot of cards these days (take a look at the newly released 8600 GTS, GT and 8500 GT from Nvidia) have hardware accelerated H.264 decoding, along with lots of other goodies the GMA950 doesn't support. These would be a boon to mac users, considering the bulk of iTunes media is in this format (or so I believe), along with the newer Hi Def disk formats.

    Since I first wrote this I thought it would be interesting to see if the Intel iMacs had a similar port, and they do. Therefore, this could conceivably be done on an iMac as well - it wouldn't apply to the internal display, but it would be a nice feature to have nonetheless.
     
  6. Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #6
    Under Windows the decode acceleration may work. Under OSX it won't work, at least at the moment, as the available drivers don't support it and the playback apps don't either.
     
  7. macrumors 68040

    iW00t

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    #7
    It is a good idea but how do you propose it is going to work? You will have to cut a hole in the drive cradle to snake the ribbon cables through...
     
  8. macrumors 604

    Cave Man

    #8
    Wouldn't replacing the processor with a C2D that's equivalent or faster also bump up the graphics speed, since the graphics are handled by the cpu?

    Is there any reason why a mini can't be repacked into a standard PC minitower? Does the SATA bus support two (or more) drives? Does the PATA bus support two drives (master/slave)? I'm just wondering what you could squeeze out of one of these buggers.
     
  9. macrumors 6502

    RedDragon870503

    Joined:
    Sep 6, 2006
    #9

    I think just the system memory is shared in this integration; not processor cycles. I may be wrong.
     
  10. job
    macrumors 68040

    job

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    #10
    While you are correct, I doubt there are any top of the range GPUs that would actually *fit* into the Mini.

    This seems like a pretty neat idea, kudos to the OP. I'll be watching this thread with a lot of interest.
     
  11. thread starter macrumors regular

    Joined:
    Apr 5, 2007
    #11
    That is indeed correct. Not only could you (potentially) notice an increase due to hardware acceleration that is not available in the GMA950 chipset, but also the onboard ram could be released for other activities.

    SATA only supports one device per bus, but I believe you can get sata "switches" to share that bus amongst many devices. Not sure how they work though, or if they'd work in the mini. I don't know if the mini pata bus supports more then one device. I can't see any reason why a mini couldn't fit in a tower case, although there would be a lot of moding involved.

    I don't think that _any_ discrete GC could fit in the mini - that's partly why I suggested that this would mean that dedicated users would have to sacrifice the "good looks" of the mini for performance. One could potentially put the guts in a pretty case though - perhaps we should resurrect the cube, as a frankenmini case?

    By the way, if anyone has a broken/dead/old/disused intel mini they want to sacrifice to me, I'd be happy to take it under my wing. I'd love to try this out. Perhaps I should hit up my local apple store (Next Byte - sadly, we don't have an official apple store where I live) to see if they have anything I can have for cheap/free.
     
  12. job
    macrumors 68040

    job

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    #12
    Let's keep this going!

    Are refurb'ed Mini's from the Apple store too expensive?
     
  13. macrumors 68040

    Pressure

    Joined:
    May 30, 2006
    Location:
    Denmark
    #13
    Seriously, you wouldn't be able to tell a difference unless you were looking at benchmark results.

    AGP 8x is still able to keep up with PCI-Express 16x.

    Admittedly a PCI-Express x1 would be seriously limiting for any graphic card, considering it is only 250MB/s.
     
  14. thread starter macrumors regular

    Joined:
    Apr 5, 2007
    #14
    I just checked the Apple refurb store, and they don't seem to have a refurb mini (If I'm using it right). I was hoping the local store would have some that have been completely fried, but now I'm thinking that they have to send these sorts of rejects back to apple for refurbishment - ie, they're not going to let me just walk off with one. Still, I'll check.

    As to "too expensive", I'm currently using a G3 iMac (400mhz, DV) that I got for free off a friend. I have about 40 dollars (AUD) to my name right now. I don't think I can even afford a shuffle u_u
     
  15. job
    macrumors 68040

    job

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    in transit
    #15
    What about craigslist?

    You might be able to barter and swap for one...
     
  16. thread starter macrumors regular

    Joined:
    Apr 5, 2007
    #16
    There's nothing on my local craigslist and ebay is way out of my price range. I have, however, left my name and number with several of the local apple resellers, but I don't expect much - they all told me they sent defective units back to apple for a rebate u_u

    All I really need is the logic board, I can get everything else from the local computer shops.
     
  17. macrumors 6502a

    Joined:
    May 22, 2005
    Location:
    Bristol, UK
    #17
    Interesting idea, love to see this succeed.
     
  18. macrumors newbie

    Mac Migs

    Joined:
    Apr 25, 2007
    #18
    Saw this on Ebay although it says it's not working. Could it possibly be repaired...?

    Mac Mini Logic Board
     
  19. thread starter macrumors regular

    Joined:
    Apr 5, 2007
    #19
    Hey Gordy. I've seen you around the web before - in fact, your thread on a water cooled Cubit 3 inspired me to make my own high powered Cubit. Thanks ^_^

    WRT that logic board - the seller shows that it has been damaged. With these sorts of small boards drilling through the pcb is a DANGEROUS idea. What happens is that the inner copper layers often "smudge", shorting together vertically. If the seller (or whoever drilled the hole) didn't go through any tracks and didn't perminantly damage it with the short, it might be salvageable. I'm not sure if I have the necessary skills to fix it though. Still, there's a few days left on the auction. I can read up on my l33t pcb repair sk1llz.
     
  20. job
    macrumors 68040

    job

    Joined:
    Jan 25, 2002
    Location:
    in transit
    #20
    I checked some US based retailers to see if they had any logic boards available. None of them did, but you might want to keep your eye on them in the future:

    www.smalldog.com
    www.powermax.com
    www.ifixit.com

    Just wondering: Wouldn't a Macbook logic board work as well?
     
  21. macrumors 6502a

    Joined:
    May 22, 2005
    Location:
    Bristol, UK
    #21
    I like to get around :D

    I still need to sort out modding my cubit, moving house and having a baby have killed my modding time of late :( On the plus side my garage is finally water tight so I can build my workshop yay!


    Back on topic, I wonder if there is any mini PCI-e to the format of laptop graphics cards that dell and alienware used to use that are "upgradeable". I forget the name for them, but they would be more likely to fit in the mac mini.

    I believe they were nVidia cards, and some of the intel iMac's use a similiar format? I can't seem to find a great deal of info about the cards.
     
  22. macrumors 68040

    Pressure

    Joined:
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    Location:
    Denmark
    #22
    You must be thinking of NVIDIAs MXM and ATis AXIOM graphics modules.
     
  23. macrumors 6502a

    Joined:
    May 22, 2005
    Location:
    Bristol, UK
    #23
  24. macrumors 68020

    Jasonbot

    Joined:
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    #24
    If this is possible would you be able to disable the gma950 to save the shared RAM from it's usual fate and thus make an even more resourceful mini.
     
  25. thread starter macrumors regular

    Joined:
    Apr 5, 2007
    #25
    Possibly - I'm not sure if simply not using the GMA950 shuts it down. I have a feeling that if you can disable the display, you free up the memory reserved for that display for general use.

    This would have a few more benefits beyond expanding video abilities. Modern video cards also do a lot of the image processing in hardware, to free up cpu cycles. I believe the GMA950 doesn't support everything in hardware, so it needs the processor to "help" it sometimes. Basically, even if the pci-e x1 bus limits the overall performance of the graphics card you would probably still see overall system performance gains, simply because you're freeing up resources to be used elsewhere.

    I'm not familiar with the Macbook logic board, but if it uses the GMA950 (it does) and if it has a slot for an airport card (it does), then it's a safe bet that it may be possible. The mini is just less of a financial investment, and usually the one that people complain the most about not being able to upgrade.
     

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