Introduction

The iMac G3 had onboard video which usually means no upgrade-ability. The iMac developers found a way to allow video upgrade-ability (sort of); they built 2MB on to the logic board to power the ATI 3D Rage Pro Turbo PCI, and added a video ram DIMM slot on the motherboard allowing users to upgrade their video ram using proprietary Apple DIMMs.

The iMac G3. This was a great computer for the time, and had plenty of features.
  • The iMac G3. This was a great computer for the time, and had plenty of features.

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Start by flipping the iMac upside-down. It may help to lay it on a towel, so you don't damage the screen, or scratch the face.
  • Start by flipping the iMac upside-down. It may help to lay it on a towel, so you don't damage the screen, or scratch the face.

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Remove this Phillips screw. Using a flathead screwdriver, work your way around the bottom cover, until it comes off. Then, lift the bottom cover up and out, and set it aside.
  • Remove this Phillips screw.

  • Using a flathead screwdriver, work your way around the bottom cover, until it comes off.

  • Then, lift the bottom cover up and out, and set it aside.

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Now, remove the DB-15 Video connector from the logic board. It may be helpful to use a Phillips screwdriver to remove the thumbscrews. It may be helpful to use a Phillips screwdriver to remove the thumbscrews.
  • Now, remove the DB-15 Video connector from the logic board.

  • It may be helpful to use a Phillips screwdriver to remove the thumbscrews.

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Remove the power cable from the logic board assembly. Remove the power cable from the logic board assembly. Remove the power cable from the logic board assembly.
  • Remove the power cable from the logic board assembly.

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Remove the front panel connector. Remove the front panel connector.
  • Remove the front panel connector.

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Now, remove these Phillips screws. Now, grab the logic board assembly by the piece of plastic, and lift it out. Now, grab the logic board assembly by the piece of plastic, and lift it out.
  • Now, remove these Phillips screws.

  • Now, grab the logic board assembly by the piece of plastic, and lift it out.

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The logic board assembly. This is the heart of the computer, it contains the motherboard, CPU, RAM, V-RAM, PRAM battery, the hard drive, and the optical drive.
  • The logic board assembly. This is the heart of the computer, it contains the motherboard, CPU, RAM, V-RAM, PRAM battery, the hard drive, and the optical drive.

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The Video-RAM DIMM slot is located on top of the logic board. Most people confuse this with the system RAM which is hidden under the CPU Shield. The GPU: an ATI 3D Rage Pro Turbo PCI with 2MB onboard + the video RAM DIMM:
  • The Video-RAM DIMM slot is located on top of the logic board. Most people confuse this with the system RAM which is hidden under the CPU Shield.

  • The GPU: an ATI 3D Rage Pro Turbo PCI with 2MB onboard + the video RAM DIMM:

  • The Video RAM DIMM:

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To remove the V-RAM, push the retaining tabs out, and the DIMM should pop up, then pull it out. The 2MB of V-RAM soldered to the logic board: According to what I've read, the iMac will support 10MB Total V-RAM, 2MB onboard, 8MB DIMM.
  • To remove the V-RAM, push the retaining tabs out, and the DIMM should pop up, then pull it out.

  • The 2MB of V-RAM soldered to the logic board:

  • According to what I've read, the iMac will support 10MB Total V-RAM, 2MB onboard, 8MB DIMM.

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Conclusion

To reassemble your device, follow these instructions in reverse order.

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Chris Green

Member since: 10/11/2009

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One Comment

where can I buy a 8mb video ram chip

Nicholas - Reply

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