IMac G5

The iMac G5 was a series of desktop Macintosh computers designed and built by Apple Inc. using the PowerPC chip architecture. It was the last line of iMac computers that used a PowerPC chip, making it the last of the iMacs that could natively run Mac OS 9 (Classic) applications.

In August 2004, the iMac design was overhauled. By this time, the PowerPC 970 chip had been released and was being used in the Power Mac G5 line. Famously, the Power Mac G5 needed multiple fans in a large casing because of the larger heat output from the PowerPC 970.

Apple's new iMac design managed to incorporate the PowerPC 970 into an all-in-one design with a distinctive form factor. The new design of the iMac used the same 17 and 20-inch widescreen LCDs, with all of the main logic board and optical drive mounted directly behind the LCD panel; this gave the appearance of a thickened desktop LCD monitor.

The iMac G5 was first released in August 2004 (known as Rev A) as a 1.8 GHz 20-inch model, along with the simultaneously introduced 17-inch 1.6 GHz and 1.8 GHz models. All featured a revolutionary integrated all-in-one enclosure approximately two inches deep with an advanced cooling system controlled by the operating system. At low CPU loads this rendered the iMac G5 virtually silent.

The iMac G5 was updated in March 2005 (Rev B) with the model called the Ambient Light Sensor or ALS iMac G5. It replaced the first generation iMac G5 and has a handful of configuration differences - more RAM, a larger hard drive, improved graphics, Gigabit Ethernet, and standard AirPort Extreme (802.11g) and Bluetooth 2.0+EDR.

The iMac G5 was updated again in October 2005 (Rev C), adding an iSight webcam mounted above the LCD, and Apple's Front Row media interface. Improvements included faster processors, more RAM, a larger hard drive, and improved graphics. Notably this became the first Apple computer to use the PCI Express expansion bus and DDR2 SDRAM, adding these features shortly before they were incorporated into the Power Mac G5. This version had a slightly bowed back and lacked the VESA Flat Display Mounting Interface of the earlier iMac G5s.

Although this iMac G5 looked like the two previous revisions, in fact it had a completely new and thinner case which allowed detailed design improvements including cooling and performance increases. This case, unlike the previous models, opened only from the front and requires the LCD screen to be removed before internal components can be accessed.

Apple recommend no user serviceable items other than RAM which is accessible through a small door in the base edge of the iMac, however, in the intervening years many excellent guides and videos have been posted on the internet to support replacing some internals including the HDD and optical drives, but doing so would void any remaining Apple warranty.

The iSight iMac G5 has few reported issues although a potential problem exists with the optical drive - some brands of writable optical media (which are a little thicker than standard) can catch on the outer (iMac case) bezel resulting either in the CD/DVD reappearing on the desktop (a few seconds after the eject command/button), or in extreme cases 'popping' out completely onto the desktop as the force of the eject mechanism overcomes the disc catching on the bezel. The solution to this is to isolate those brands of disc and not use them.

The iSight iMac G5 PPC was caught in Apple's early 2006 scramble onto Intel and was replaced with the Intel-based iMac on January 10, 2006, beginning the 6 month transition of Apple's entire line of computers to Intel based motherboards.