iMac Ambient Light Sensor 2005

Like their predecessors, the "Ambient Light Sensor" iMac G5 models feature a chassis that rests on an adjustable aluminum stand and supports the VESA mounting standard for versatile placement. As their name indicates, these models include a sensor below the display that dims the sleep indicator light in low-light conditions, a thoughtful feature for use in a bedroom.

The iMac G5/2.0 20-Inch (ALS) is equipped with a 2.0 GHz PowerPC 970 (G5) processor with an optimized AltiVec "Velocity Engine" and a 512k on-chip L2 cache. It includes 512 MB of 400 MHz PC3200 DDR SDRAM, a 250 GB (7200 RPM) Serial ATA hard drive, a vertical slot-loading 8X DVD-R/CD-RW "SuperDrive", and ATI Radeon 9600 graphics with 128 MB of DDR SDRAM (AGP 8X). The system has built-in stereo speakers beneath the 20" TFT Active Matrix LCD (1680x1050) designed to "bounce sound off the desk below". Standard connectivity includes Firewire "400", USB 2.0, AirPort Extreme (802.11g), and Bluetooth 2.0+EDR.

The iMac G5 is cooled by three low-noise blowers that draw air through the speaker grill, with heat dissipating from a top-rear vent.

The 20-inch iMac G5 (ALS) was considered an attractive option for many users due to its expansive display and solid performance. With an improved processor speed and enhanced graphics over the original iMac G5, this model offered a more fluid computing experience while retaining its beautiful design. The ambient light sensor, which automatically adjusted the sleep indicator's brightness, was noted as a thoughtful feature, particularly for use in environments like a bedroom. However, some early units were reported to have startup issues due to capacitor problems, with repair information being shared within the user community. Nevertheless, it was generally regarded as a well-realized all-in-one machine that set the template for future iMac designs, and its quiet cooling system was also highly praised. Although it was on the market for a short period before the iSight model's debut, this iMac represented a steady evolution in the PowerPC era.