OSX 10.8 and Late 2006 iMac

Discussion in 'Apple' started by gtr, Jul 26, 2012.

  1. gtr

    gtr Guest

    I note in arstechnica review that it says:

    "Mountain Lion continues the inexorable march of progress by dropping
    support for 32-bit kernel extensions and requiring a Mac that can run
    the 64-bit kernel. This currently excludes many Macs that have 64-bit
    processors, including the *Late 2006 iMac* and many years of Mac mini
    and Mac Pro models."

    Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    when a friend upgraded at about the same point my PPC died.

    I assume this means I don't get to play. Please advise if there is a
    difference of opinion.
    gtr, Jul 26, 2012
    #1
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  2. gtr

    sbt Guest

    In article <2012072608514720233-xxx@yyyzzz>, gtr <> wrote:

    > I note in arstechnica review that it says:
    >
    > "Mountain Lion continues the inexorable march of progress by dropping
    > support for 32-bit kernel extensions and requiring a Mac that can run
    > the 64-bit kernel. This currently excludes many Macs that have 64-bit
    > processors, including the *Late 2006 iMac* and many years of Mac mini
    > and Mac Pro models."
    >
    > Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    > when a friend upgraded at about the same point my PPC died.
    >
    > I assume this means I don't get to play. Please advise if there is a
    > difference of opinion.
    >


    You don't get to play with that iMac (requires mid-2007 or later iMac).
    Similarly, although my iMac and MacPro qualify, my MacBood doesn't (and
    my Mac Pro still doesn't get to use AirDrop).

    --
    Spenser
    sbt, Jul 26, 2012
    #2
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  3. gtr

    Alan Browne Guest

    On 2012-07-26 11:51 , gtr wrote:
    > I note in arstechnica review that it says:
    >
    > "Mountain Lion continues the inexorable march of progress by dropping
    > support for 32-bit kernel extensions and requiring a Mac that can run
    > the 64-bit kernel. This currently excludes many Macs that have 64-bit
    > processors, including the *Late 2006 iMac* and many years of Mac mini
    > and Mac Pro models."
    >
    > Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    > when a friend upgraded at about the same point my PPC died.
    >
    > I assume this means I don't get to play. Please advise if there is a
    > difference of opinion.


    David Empson posted on this a few times. Search Google Groups.

    But I'm pretty sure you're screwed for ML as my iMac (mid or late 2007)
    is the oldest iMac that ML will work on.

    Curiously, when I had SL the kernel was 32 b and I couldn't get 64 b to
    load, but I noticed recently that with Lion it's 64 b.

    This also likely means that Lion will be the last major OS upgrade for
    my iMac. Then again I do have the replacement lust bubbling up. Damn
    thing is this iMac works so well for 99% of what I do that replacing it
    seems silly.

    --
    "Civilization is the limitless multiplication of unnecessary necessities."
    -Samuel Clemens.
    Alan Browne, Jul 26, 2012
    #3
  4. gtr

    David Empson Guest

    gtr <> wrote:

    > I note in arstechnica review that it says:
    >
    > "Mountain Lion continues the inexorable march of progress by dropping
    > support for 32-bit kernel extensions and requiring a Mac that can run
    > the 64-bit kernel. This currently excludes many Macs that have 64-bit
    > processors, including the *Late 2006 iMac* and many years of Mac mini
    > and Mac Pro models."
    >
    > Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    > when a friend upgraded at about the same point my PPC died.
    >
    > I assume this means I don't get to play. Please advise if there is a
    > difference of opinion.


    There is absolutely no chance you will be able to get Mountain Lion
    working on that iMac model.

    The critical problem in this case is the graphics processing unit (GPU).
    Mountain Lion has established a minimum baseline for GPU capabilities
    (probably based on it being able to support OpenCL and certain OpenGL
    features). Your Mac's GPU is old enough not to support those features,
    and it cannot be replaced, so Apple did not support your Mac for
    Mountain Lion.

    The GPU is what caused Mountain Lion to not be supported on the
    following models. I've listed the GPU in each case.

    iMac (Late 2006): Intel GMA 950, ATI Radeon X1600, NVIDIA GeForce 7300GT
    or 7600GT.

    Mac Mini (Mid 2007): Intel GMA 950.

    MacBook (Late 2006, Mid 2007): Intel GMA 950.

    MacBook (Late 2007, Mid 2008, Late 2008): Intel GMA X3100.

    MacBook Air (Early 2008): Intel GMA X3100.

    MacBook Pro (Late 2006): ATI Radeon X1600.

    Xserve (Late 2006, Early 2008): ATI Radeon X1300.

    That covers all models with a non-replaceable dedicated GPU in the
    NVIDIA 7000 or ATI 1000 series, plus the older very limited Intel
    integrated GPUs.

    The 2006 models and some of the 2007 models in that list also have
    32-bit EFI (firmware) which prevents them easily running a 64-bit
    kernel.

    Mountain Lion requires a 64-bit kernel, and this is the reason the Mac
    Pro (Mid 2006 and Early 2007) were dropped, since they would have been
    the only models needing a special workaround to get the 64-bit kernel
    working. (All other models with 32-bit EFI had a non-replaceable GPU
    which wasn't good enough.)

    The ATI 1000 series and NVIDIA 7000 series already have 64-bit kernel
    extensions in Lion, so the reason models with those GPUs were dropped
    was not because of the 64-kit kernel requirement, but because the GPU
    wasn't good enough.

    Some Mac Pros in the Mid 2006 and Early 2007 series were supplied with
    GPUs in the above list (or similar models), but the GPU in the Mac Pro
    is on a slot-based PCI Express graphics card and can be replaced with a
    later graphics card that has a better GPU. After doing that, these Mac
    Pro models apparently can be made to run Mountain Lion via a somewhat
    complex and unsupported hack, but I haven't seen confirmation of that
    method working with the public release of Mountain Lion, only early
    developer releases.

    The Xserves might have a similar option, if they have a free PCI Express
    slot with sufficient lanes in which a suitable graphics card could be
    installed, as long as the built-in ATI Radeon X1300 can be completely
    ignored.

    The Late 2006 MacBook Pro has an ExpressCard slot, so in theory it might
    be possible to install a better GPU externally and get Mountain Lion
    working with a similar hack, but I expect the number of PCI Express
    lanes available on the ExpressCard slot would rule that out. In
    addition, that model has a 3 GB memory limit, making it a poor candidate
    for running Mountain Lion with enough RAM to perform well. (The Mac Pro
    and Xserve can support at least 16 GB of RAM.)

    All iMac, Mac Mini, MacBook and MacBook Air models in the above list
    have no internal slots so have no way to install a different GPU,
    therefore no way to hack around the GPU requirement in Mountain Lion.

    --
    David Empson
    David Empson, Jul 27, 2012
    #4
  5. gtr

    David Empson Guest

    Alan Browne <> wrote:

    > On 2012-07-26 11:51 , gtr wrote:
    > > I note in arstechnica review that it says:
    > >
    > > "Mountain Lion continues the inexorable march of progress by dropping
    > > support for 32-bit kernel extensions and requiring a Mac that can run
    > > the 64-bit kernel. This currently excludes many Macs that have 64-bit
    > > processors, including the *Late 2006 iMac* and many years of Mac mini
    > > and Mac Pro models."
    > >
    > > Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    > > when a friend upgraded at about the same point my PPC died.
    > >
    > > I assume this means I don't get to play. Please advise if there is a
    > > difference of opinion.

    >
    > David Empson posted on this a few times. Search Google Groups.


    (I've just done a detailed response to the OP.)

    > But I'm pretty sure you're screwed for ML as my iMac (mid or late 2007)
    > is the oldest iMac that ML will work on.
    >
    > Curiously, when I had SL the kernel was 32 b and I couldn't get 64 b to
    > load, but I noticed recently that with Lion it's 64 b.


    With Snow Leopard, Apple only implemented the 64-bit kernel on 2008 and
    later models in the iMac, Mac Pro, Xserve and MacBook Pro families, plus
    the 2010 Mac Mini (specifically for Mac OS X Server).

    The Mid 2007 iMac and MacBook Pro models may have been excluded based on
    an executive decision rather than for technical reasons, though it is
    possible Apple just hadn't got around to implementing 64-bit kernel
    extensions required to support some older hardware components.

    It appears late 2008 or newer MacBook, MacBook Air and Mac Mini models
    were limited to the 32-bit kernel in Snow Leopard based on an executive
    decision. Earlier models in those series had Intel integrated graphics
    which never got a 64-bit kernel extension, so they cannot run the 64-bit
    kernel on any OS version.

    In Lion, 64-bit kernel support was extended back to the Mid 2007 iMac
    and MacBook Pro, and to all MacBook, MacBook Air and Mac Mini models
    with NVIDIA integrated graphics.

    > This also likely means that Lion will be the last major OS upgrade for
    > my iMac.


    Your mid 2007 iMac can run Mountain Lion, so was that a typo or do you
    have an as yet unspecified reason for not upgrading to Mountain Lion?

    We can only speculate on what the minimum requirements will be for a mid
    2013 version of OS X. It is quite possible it won't increase the minimum
    requirements at all.

    Apple's seemingly arbitrary cutoffs for supporting older models in new
    OS versions usually have a valid technical reason, and they almost
    always support models for at least three years after they were
    discontinued, popular models for closer to four years minimum.

    I have already noted that the minimum RAM requirement can't go above 2
    GB for a while yet, because the MacBook Air was sold until mid 2012 with
    only 2 GB in the entry level model, suggesting mid 2015 is the earliest
    Apple could require more than 2 GB of RAM for a new OS release.

    From a quick glance at the 2007 and 2008 models still supported by
    Mountain Lion, the feature which seems most likely to be dropped first
    is support for the NVIDIA 8000 and ATI 2000 series GPUs.

    That would bring the starting point up to these models:

    iMac (Early 2009)
    Mac Mini (Early 2009) - no change
    Mac Pro (Early 2009), or possibly Early 2008 as long as GPU replaced
    MacBook (Early 2009, or Late 2008 Aluminium) - no change
    MacBook Air (Late 2008) - no change
    MacBook Pro (Late 2008)
    Xserve (Early 2009) - no change

    That falls within a similar cutoff time window to other OS X releases,
    but is unusual in that it drops support for older iMac and MacBook Pro
    models without affecting all the low end models.

    If the support for the NVIDIA 9000 series was also dropped, the cutoff
    would shift as late as October 2010 for some models, June 2010 or
    earlier for most. That is too close to a mid 2013 OS release, but might
    be acceptable for a mid 2014 OS release.

    > Then again I do have the replacement lust bubbling up. Damn thing is this
    > iMac works so well for 99% of what I do that replacing it seems silly.



    --
    David Empson
    David Empson, Jul 27, 2012
    #5
  6. gtr

    Lewis Guest

    In message <2012072608514720233-xxx@yyyzzz>
    gtr <> wrote:
    > I assume this means I don't get to play.


    Not officially, no.

    >Please advise if there is a difference of opinion.


    It is possible. It is not easy, but it is possible.

    You need a spare drive you can format with a MBR (so it must be 2TB or
    smaller and at least 10GB) and you need a recent copy of Chameleon, but
    it is *possible*.

    I do *not* recommend it.

    --
    I get the feeling that some people's idea of heaven is an "I told you
    so" T-shirt - mmalc
    Lewis, Jul 27, 2012
    #6
  7. gtr

    Lewis Guest

    In message <1knw0bu.8crz3x1lva687N%>
    David Empson <> wrote:
    >> Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    >> when a friend upgraded at about the same point my PPC died.


    > There is absolutely no chance you will be able to get Mountain Lion
    > working on that iMac model.


    Ah, right. I should have looked up the video card. The Late 2006 iMac
    has an X1600 and there are not, nor have there ever been, nor will there
    ever be, 64 bit drivers for that card. David is right, you are 100% out
    of luck.

    > The ATI 1000 series and NVIDIA 7000 series already have 64-bit kernel
    > extensions in Lion,


    Are you sure? I thought they faked it and loaded the 32 bit drivers? Or
    is it just the lack of OpenCL?

    I certainly see links to people saying they don't have 64 bit drivers,
    but they are just web forum posters, nothing reliable.

    > Some Mac Pros in the Mid 2006 and Early 2007 series were supplied with
    > GPUs in the above list (or similar models), but the GPU in the Mac Pro
    > is on a slot-based PCI Express graphics card and can be replaced with a
    > later graphics card that has a better GPU. After doing that, these Mac
    > Pro models apparently can be made to run Mountain Lion via a somewhat
    > complex and unsupported hack, but I haven't seen confirmation of that
    > method working with the public release of Mountain Lion, only early
    > developer releases.


    There was a hack that worked in the DP1. That stopped working in DP2.
    There is an entirely different hack that works if you have a 5750/5770
    GPU.

    --
    Oh, he's just like any other man, only more so.
    Lewis, Jul 27, 2012
    #7
  8. gtr

    David Empson Guest

    Lewis <> wrote:

    > In message <1knw0bu.8crz3x1lva687N%>
    > David Empson <> wrote:
    > >> Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    > >> when a friend upgraded at about the same point my PPC died.

    >
    > > There is absolutely no chance you will be able to get Mountain Lion
    > > working on that iMac model.

    >
    > Ah, right. I should have looked up the video card. The Late 2006 iMac
    > has an X1600 and there are not, nor have there ever been, nor will there
    > ever be, 64 bit drivers for that card. David is right, you are 100% out
    > of luck.
    >
    > > The ATI 1000 series and NVIDIA 7000 series already have 64-bit kernel
    > > extensions in Lion,

    >
    > Are you sure? I thought they faked it and loaded the 32 bit drivers? Or
    > is it just the lack of OpenCL?


    Let me rephrase: they _appear_ to have 64-bit kernel extensions in Lion,
    in that the executable has x86-64 code in it.

    The 2008 Xserve runs with a 64-bit kernel in Snow Leopard and Lion, and
    it has an ATI Radeon X1300, therefore at least the ATI X1300 kext must
    have functional 64-bit code. Harder to tell for the ATI X1600/X1900 and
    NVIDIA 7300/7600, because none of the models supplied with those GPUs
    had 64-bit EFI.

    > I certainly see links to people saying they don't have 64 bit drivers,
    > but they are just web forum posters, nothing reliable.
    >
    > > Some Mac Pros in the Mid 2006 and Early 2007 series were supplied with
    > > GPUs in the above list (or similar models), but the GPU in the Mac Pro
    > > is on a slot-based PCI Express graphics card and can be replaced with a
    > > later graphics card that has a better GPU. After doing that, these Mac
    > > Pro models apparently can be made to run Mountain Lion via a somewhat
    > > complex and unsupported hack, but I haven't seen confirmation of that
    > > method working with the public release of Mountain Lion, only early
    > > developer releases.

    >
    > There was a hack that worked in the DP1. That stopped working in DP2.
    > There is an entirely different hack that works if you have a 5750/5770
    > GPU.


    OK, thanks for the correction.

    --
    David Empson
    David Empson, Jul 27, 2012
    #8
  9. gtr

    Alan Browne Guest

    On 2012-07-26 20:24 , David Empson wrote:
    > Alan Browne <> wrote:
    >
    >> On 2012-07-26 11:51 , gtr wrote:
    >>> I note in arstechnica review that it says:
    >>>
    >>> "Mountain Lion continues the inexorable march of progress by dropping
    >>> support for 32-bit kernel extensions and requiring a Mac that can run
    >>> the 64-bit kernel. This currently excludes many Macs that have 64-bit
    >>> processors, including the *Late 2006 iMac* and many years of Mac mini
    >>> and Mac Pro models."
    >>>
    >>> Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    >>> when a friend upgraded at about the same point my PPC died.
    >>>
    >>> I assume this means I don't get to play. Please advise if there is a
    >>> difference of opinion.

    >>
    >> David Empson posted on this a few times. Search Google Groups.

    >
    > (I've just done a detailed response to the OP.)
    >
    >> But I'm pretty sure you're screwed for ML as my iMac (mid or late 2007)
    >> is the oldest iMac that ML will work on.
    >>
    >> Curiously, when I had SL the kernel was 32 b and I couldn't get 64 b to
    >> load, but I noticed recently that with Lion it's 64 b.

    >
    > With Snow Leopard, Apple only implemented the 64-bit kernel on 2008 and
    > later models in the iMac, Mac Pro, Xserve and MacBook Pro families, plus
    > the 2010 Mac Mini (specifically for Mac OS X Server).
    >
    > The Mid 2007 iMac and MacBook Pro models may have been excluded based on
    > an executive decision rather than for technical reasons, though it is
    > possible Apple just hadn't got around to implementing 64-bit kernel
    > extensions required to support some older hardware components.
    >
    > It appears late 2008 or newer MacBook, MacBook Air and Mac Mini models
    > were limited to the 32-bit kernel in Snow Leopard based on an executive
    > decision. Earlier models in those series had Intel integrated graphics
    > which never got a 64-bit kernel extension, so they cannot run the 64-bit
    > kernel on any OS version.



    > In Lion, 64-bit kernel support was extended back to the Mid 2007 iMac
    > and MacBook Pro, and to all MacBook, MacBook Air and Mac Mini models
    > with NVIDIA integrated graphics.


    Good for both my SO's MBA and my son's MBP.
    >
    >> This also likely means that Lion will be the last major OS upgrade for
    >> my iMac.

    >
    > Your mid 2007 iMac can run Mountain Lion, so was that a typo or do you
    > have an as yet unspecified reason for not upgrading to Mountain Lion?


    Sorry I meant ML will likely be the last.

    >
    > We can only speculate on what the minimum requirements will be for a mid
    > 2013 version of OS X. It is quite possible it won't increase the minimum
    > requirements at all.


    It seems to march forward as a 5 year (ish) span, so the two laptops
    here may be covered but my iMac may not.

    >
    > Apple's seemingly arbitrary cutoffs for supporting older models in new
    > OS versions usually have a valid technical reason, and they almost
    > always support models for at least three years after they were
    > discontinued, popular models for closer to four years minimum.


    Good to hear. Perhaps that all of the machines here are 64 b "able" and
    that that is not likely to be upped to 128 b for a long time will give
    us a golden era.

    > I have already noted that the minimum RAM requirement can't go above 2
    > GB for a while yet, because the MacBook Air was sold until mid 2012 with
    > only 2 GB in the entry level model, suggesting mid 2015 is the earliest
    > Apple could require more than 2 GB of RAM for a new OS release.


    Perfect. That's what's in the SO's MBA. It would be nice if that could
    be updates to 4 GB. OTOH for her needs 2 GB is more than sufficient
    (web, Word, Excel, photo viewing/editing).

    >
    > From a quick glance at the 2007 and 2008 models still supported by
    > Mountain Lion, the feature which seems most likely to be dropped first
    > is support for the NVIDIA 8000 and ATI 2000 series GPUs.


    Why would they drop that support? It's stable stuff.

    >
    > That would bring the starting point up to these models:
    >
    > iMac (Early 2009)
    > Mac Mini (Early 2009) - no change
    > Mac Pro (Early 2009), or possibly Early 2008 as long as GPU replaced
    > MacBook (Early 2009, or Late 2008 Aluminium) - no change
    > MacBook Air (Late 2008) - no change
    > MacBook Pro (Late 2008)
    > Xserve (Early 2009) - no change
    >
    > That falls within a similar cutoff time window to other OS X releases,
    > but is unusual in that it drops support for older iMac and MacBook Pro
    > models without affecting all the low end models.
    >
    > If the support for the NVIDIA 9000 series was also dropped, the cutoff
    > would shift as late as October 2010 for some models, June 2010 or
    > earlier for most. That is too close to a mid 2013 OS release, but might
    > be acceptable for a mid 2014 OS release.


    Too much info!

    --
    "Civilization is the limitless multiplication of unnecessary necessities."
    -Samuel Clemens.
    Alan Browne, Jul 27, 2012
    #9
  10. gtr

    Mr. Strat Guest

    In article <2012072608514720233-xxx@yyyzzz>, gtr <> wrote:

    > I note in arstechnica review that it says:
    >
    > "Mountain Lion continues the inexorable march of progress by dropping
    > support for 32-bit kernel extensions and requiring a Mac that can run
    > the 64-bit kernel. This currently excludes many Macs that have 64-bit
    > processors, including the *Late 2006 iMac* and many years of Mac mini
    > and Mac Pro models."
    >
    > Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    > when a friend upgraded at about the same point my PPC died.
    >
    > I assume this means I don't get to play. Please advise if there is a
    > difference of opinion.


    Cheer up! You're not missing anything.
    Mr. Strat, Jul 27, 2012
    #10
  11. gtr

    gtr Guest

    On 2012-07-27 00:23:58 +0000, David Empson said:

    > There is absolutely no chance you will be able to get Mountain Lion
    > working on that iMac model.
    >
    > The critical problem in this case is the graphics processing unit (GPU).
    > Mountain Lion has established a minimum baseline for GPU capabilities
    > (probably based on it being able to support OpenCL and certain OpenGL
    > features). Your Mac's GPU is old enough not to support those features,
    > and it cannot be replaced, so Apple did not support your Mac for
    > Mountain Lion.


    Thanks to all for verifying my antique machine's demise.

    I don't intend to do this, but inquired about updating the graphics
    card when I found out a few months ago that the Final Cut demo (and the
    application), would not run because of my graphics card. The local Mac
    shop told me I could replace the graphics card.

    In theory, if I do (which I won't), could I then upgrade to ML?
    gtr, Jul 27, 2012
    #11
  12. gtr

    gtr Guest

    On 2012-07-27 14:05:15 +0000, Mr. Strat said:

    > In article <2012072608514720233-xxx@yyyzzz>, gtr <> wrote:
    >
    >> I note in arstechnica review that it says:
    >>
    >> "Mountain Lion continues the inexorable march of progress by dropping
    >> support for 32-bit kernel extensions and requiring a Mac that can run
    >> the 64-bit kernel. This currently excludes many Macs that have 64-bit
    >> processors, including the *Late 2006 iMac* and many years of Mac mini
    >> and Mac Pro models."
    >>
    >> Sadly I have such a Late 2006 IMac, genrously bequeathed 3 years ago
    >> when a friend upgraded at about the same point my PPC died.
    >>
    >> I assume this means I don't get to play. Please advise if there is a
    >> difference of opinion.

    >
    > Cheer up! You're not missing anything.


    I'm missing plenty! But I'll wait until the Fall and hopefully the
    newest architecture before purchasing a machine to last the next 6
    years.
    gtr, Jul 27, 2012
    #12
  13. gtr

    nospam Guest

    In article <2012072711505819265-xxx@yyyzzz>, gtr <> wrote:

    > I don't intend to do this, but inquired about updating the graphics
    > card when I found out a few months ago that the Final Cut demo (and the
    > application), would not run because of my graphics card. The local Mac
    > shop told me I could replace the graphics card.


    not on an imac you can't.
    nospam, Jul 27, 2012
    #13
  14. gtr

    David Empson Guest

    Alan Browne <> wrote:

    > On 2012-07-26 20:24 , David Empson wrote:


    [...]

    > > Apple's seemingly arbitrary cutoffs for supporting older models in new
    > > OS versions usually have a valid technical reason, and they almost
    > > always support models for at least three years after they were
    > > discontinued, popular models for closer to four years minimum.

    >
    > Good to hear. Perhaps that all of the machines here are 64 b "able" and
    > that that is not likely to be upped to 128 b for a long time will give
    > us a golden era.
    >
    > > I have already noted that the minimum RAM requirement can't go above 2
    > > GB for a while yet, because the MacBook Air was sold until mid 2012 with
    > > only 2 GB in the entry level model, suggesting mid 2015 is the earliest
    > > Apple could require more than 2 GB of RAM for a new OS release.

    >
    > Perfect. That's what's in the SO's MBA. It would be nice if that could
    > be updates to 4 GB. OTOH for her needs 2 GB is more than sufficient
    > (web, Word, Excel, photo viewing/editing).
    >
    > >
    > > From a quick glance at the 2007 and 2008 models still supported by
    > > Mountain Lion, the feature which seems most likely to be dropped first
    > > is support for the NVIDIA 8000 and ATI 2000 series GPUs.

    >
    > Why would they drop that support? It's stable stuff.


    If a new OS introduces a feature which requires a specific graphics
    processor capability, older GPUs are the ones most likely to be dropped.

    Apple has to weigh this against their apparent "minimum of three years
    and preferably at least four years" support window for older models.

    Therefore identifying the last model which used a particular GPU family
    gives a rough idea of the earliest point at which Apple might be
    considering dropping support for that GPU, and for all older models
    using the same GPU.

    I can only speculate as to what cutoff Apple decides to use with future
    OS versions. Things like memory and speed are out for a while because
    the MacBook Air differs markedly from other models in those areas.

    CPU architecture and GPU capabilities are the next most likely targets.

    In the CPU realm, Apple might decide to require a certain minimum level
    of SSE vector processing support, which would require dropping support
    for older Core 2 Duo processors, but that is hard to analyse without
    more research. Dropping all "Core 2 Duo" models is a possibility, but
    not before mid 2014 and probably mid 2015 (MacBook, MacBook Air and Mac
    Mini models had that processor until July 2011).

    I'd also have to do more research to identify GPU features which might
    justify dropping support for certain GPU families.


    Here are the cutoffs we've had to date with Mac OS X versions.

    Panther (10.3) dropped support for models that didn't have built-in USB.

    There was no technical reason to require USB, it just gave way to
    identify the original iMac and later models, which were all based on
    what Apple called the "new world architecture". This allowed Apple to
    stop updating kernel and driver support for hardware components in the
    older architecture models (such as the original PowerMac G3).


    Tiger (10.4) dropped support for models that didn't have built-in
    Firewire.

    This seemed completely arbitrary, as it split some iMac G3 families
    between low end models without Firewire (which are officially limited to
    Panther) and higher end models with Firewire (which are officially
    limited to Tiger). It is easy to get Tiger working on those particular
    iMac models, but earlier generations require third party support
    (XPostFacto).

    My speculation with the Tiger cutoff is that Apple wanted to drop
    support for the earliest "new world" architecture generation, including
    early iMac models and some early PowerBook G3s, but retain support for
    later/faster models. The Firewire cutoff resulted in a few oddball cases
    as far as hardware generations were concerned.

    It did have the effect of enforcing a minimum speed of a 300 MHz G3
    (slowest Blue & White PowerMac G3), but dropped support for some models
    without Firewire at 300, 333, 350 and 366 MHz.

    Requiring Firewire had the useful impact that all Macs officially
    supported by Tiger were able to be diagnosed via Firewire. All but the
    earliest also supported Firwire Target Mode.


    Leopard (10.5) dropped support for all models with G3 processors, and
    all models with G4 processors slower than 867 MHz.

    Dropping the G3 was a case of wanting to ensure every Mac running
    Leopard had Altivec support (vector processing unit in the CPU), which
    allowed Apple to make use of Altivec in the core OS and in applications
    included with Mac OS X.

    Dropping slower G4s seemed more arbitrary and was probably judged based
    on a minimum performance standard for running certain applications. If
    slower models weren't able to keep up, the end user experience may be
    unsatisfactory.

    The series most affected by the speed cutoff were the first six
    generations of PowerMac G4s. The Digital Audio (2000) and earlier series
    were not officially supported. The QuickSilver (2001) series had the
    middle model officially supported but the high end model (dual 800 GHz)
    not supported. The QuickSilver 2002 series was suppored in mid and high
    end configurations, but not low end. A third party processor upgrade
    allowed all of these to run Leopard without performance issues.

    Even on a model with its original processor, this speed cutoff was easy
    to work around, and Leopard can be made to work on Digital Audio and
    later PowerMac G4 models with no issues apart from performance.

    The previous two generations (AGP Graphics and Gigabit Ethernet) can
    also run Leopard, but are likely to run into graphics card compatibility
    issues due to lack of drivers, requiring the card to be replaced with a
    newer one.

    Leopard really cannot run on the original PowerMac G4 (PCI Graphics),
    which used an architecture based on the PowerMac G3 (Blue & White) with
    minor tweaks to get a G4 in there. The AGP Graphics model was a
    significant redesign. Leopard doesn't have kernel or driver support for
    the older logic board components.


    Snow Leopard (10.6) dropped support for all PowerPC processors.

    This was a clean architecture cutoff, allowing Apple to stop supporting
    all PowerPC hardware, and therefore not having to implement or maintain
    driver or kernel support for those models, and allowing some PowerPC
    code to be dropped from the OS and applications included with it. (Some
    PowerPC code was still needed to support Rosetta and PowerPC
    applications.)


    Lion (10.7) dropped support for all 32-bit Intel processors.

    This was also a clean architecture cutoff, allowing Apple to use 64-bit
    code everywhere and dropping some 32-bit code in the OS. (Some 32-bit
    code was stll needed to support 32-bit Intel applications.) Lion also
    dropped Rosetta, allowing all remaining PowerPC code to be removed from
    the OS.


    Mountain Lion (10.8) dropped support for models with older GPUs and
    32-bit EFI.

    This allowed the kernel to always run in 64-bit mode, and ensured all
    Macs running Mountain Lion can use OpenCL, therefore allowing Apple to
    use OpenCL in core parts of the OS. The minimum GPU standard may also
    allow OpenGL enhancements in Mountain Lion, and ensured a minimum level
    of functionality for features like Core Animation.

    --
    David Empson
    David Empson, Jul 28, 2012
    #14
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