Wednesday, February 8, 2012

Anniversaries and an iMac G4 "Sandy Bridge Mod" Pro Version?

I hadn't even realized that I failed to acknowledge an important anniversary.  The iMac G4 was introduced on January 7th, 2002 by Steve Jobs at the San Francisco Macworld.  The 20" was released later in November 18, 2003.  Then only 2 and a half years later (August 31, 2004) the iMac G4, with its sunflower inspired horizontal design, was discontinued in favor of the iMac G5's vertically oriented all-in-one.

Many reasons have been suggested to why this was done.  The cost of the neck, the difficulty in supporting increasing LCD sizes, and the cooling needs of the notoriously hot G5 processor.  I have been using one version of this as an external monitor hooked up to a mac mini and now a second version as a modernized all-in-one and it remains one of the most enjoyable desktop user experiences I have know, even 10 years later.

With my sandy bridge "genuine" mod my goal was to be as true to the original as possible, but I have been thinking about doing a version that has some extra features not found in the original.  Some of these may be possible, some of them are not.  To make extra room in the base, the optical drive will be removed.  So, I am contemplating doing a "PRO" version of the iMac G4 mod.  I have enough spare parts and I think this may be a fun alternative.  I will likely use the TMDS to DVI method and not the apple cinema display controller method.  The overall look of the iMac G4 will be changed (something I wanted to avoid in the previous mod).  Things I may add:
3M Touchscreen
  • A Touchscreen: One of my favorite mods used a resistive touchscreen and it fits this form factor quite well.  However, I did not like the glare, resolution, or touch accuracy of the resistive touchscreen.  I have however located a capacitive touchscreen that should fit in this mod.  Its flaw is that it is somewhat thick and heavy.  An alternative may be incorporating optical sensors in the bezel.
  • LED backlighting: This would be necessary to fit the touchscreen, but something that has been done in similar projects by JL7, and adds improved backlighting and power efficiency.
  • Quad Core Processor: I changed from a mobile core i7 quad core to a dual core i5 as a result of both heat production and power consumption in my latest mod.  However, a quad core i7 machine is still something I would love to do.  As well as maxing out the RAM to 8GB.
  • Native Power: Increased power needs would require a big power supply and the only one that could fit is the native supply which other modders have used.
  • Better Cooling: Use of the native PSU would require shifting of the mobo downwards.  This as well as heat generated by the quad core processor and the PSU itself would require a much more powerful cooling solution.  At the very least a large active heatsink on the CPU and a 92mm case fan.  However, an intake fan at the bottom may be needed as well.  This will use of the space that was previously used by the optical drive.
  • iSight Cam: in my G4/G5 setup, I use the iSight cam on the G5, but I have been wishing that there was one on the G4's LCD as it would be much easier to manipulate.  The microphone is already there, modifying the LCD enclosure to support an iSight may be possible.
iMac G4 iSight Mock-up

  • Apple Modification: Just to visually delineate this, I was considering altering the apple on the base.  A light up apple or IR sensor are possibilities
  • ???Improved Graphics: This one is difficult, although its something I would like to add, most of these small boards do not have PCI-Ex16 slots.  Even conversion of mini pcie is usually only to x1, and this makes it difficult to get much improvement over on chip sandy bridge graphics.  Fitting and powering a full size card would also be difficult.  I will continue to give this thought, but its probably unlikely.  Even if you wedge a mini itx in, you would have difficulty fitting even a low profile card in to the dome.  
Although this mod would involve tradeoffs including louder fans, loss of the optical drive, and loss of the exact iMac G4 appearance, there are clearly advantages as well.  The iSight, LED backlights, and touchscreen in particular are things I would love to add.  Any suggestions would be appreciated.


  1. Nice plans ! All this blog is also very nice !
    Idees for you, things I thought while reading your whole blog :
    Just look page 17 of this :

    KEEX6100 seems to support 8Gb of ram.

    About graphics : why won't you use a mini-PCI graphic card ? And a USB dungle for wifi (or no wifi at all).
    And why i7 ? i5 is soooo powerfull !
    LED backlighting sounds cool ! And this would solve the problem of having to use a voltage upconverter.

    Waiting to see more !

    (sorry, not English native)

  2. Thanks, while there are some mini PCI-E graphics cards, they usually are not traditional graphics cards and I do not believe that they would be easily compatible with OSX. Its not so much i5 vs. i7 as it is dual vs quad core mobile chip. And yes, you are right about that, though using the native power supply would supply a 24V line. And yes you are correct 8GB is supported. Thanks for the comments

  3. Incompatible ? Why would they be ? Aren't graphics cards connected trough Mini-pciE in MBPs and iMacs ? you could use AMD HD 6770M, which is used in the current MBP line...

  4. The graphics cards are soldered to the the motherboard. Some laptop graphics cards use a MXM connection, but no ECX board I have seen has MXM and even if it did, I doubt OSX would recognize it.

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