ATI Radeon X1900 XT

The ATI Radeon X1900 XT was a high-end graphics card released by Apple on August 7, 2006 as a build-to-order option for the 2006 1st-generation Mac Pro. It is based on a GPU chipset developed by ATI Technologies (which was in the process of being acquired by AMD). It was also sold separately.

Description
The Radeon X1900 XT is based on ATI's R580 XT performance graphics chip that was fabricated by TSMC on the 90 nm process. The GPU clock speed was 625 MHz, which could be boosted to 725 MHz. Unlike base consumer models, Apple offered a version that contained 512 MB of GDDR3 video RAM. The card features two dual-link DVI ports capable of driving up to two two digital displays at 2560 x 1600 pixels, such as the 30-inch Apple Cinema HD Display. With DVI to VGA Adapters, up to two analog (VGA) displays could be supported at up to 2048 x 1536 pixels. It took up the space of a double-wide PCIe 1.0 x16 slot, and required an auxiliary power cable.

The character printed on the GPU enclosure is named "Ruby", produced by RhinoFX to demonstrate and promote ATI's graphics capabilities.

Support
The Radeon X1900 XT required a minimum of Mac OS X 10.4.7 (Tiger), which was pre-installed on the 2006 Mac Pro. A separate G5 Mac Edition was made available for the Power Mac G5 in November 2006.

Issues
In September 2010, Apple announced an exchange program for a run of cards that may have had issues with distorted video being displayed. Cards eligible for exchange had serial numbers containing "V6Z" within the last 4 digits. The card could run through OS X 10.11.6 (El Capitan), though it was noted to be more stable while under OS X 10.10.5 (Yosemite).