ATI Radeon HD 3870 Mac & PC Edition

The ATI Radeon HD 3870 Mac & PC Edition was a high-end graphics card marketed by Advanced Micro Devices (AMD). It was announced on June 12, 2008 and began shipping in the following early August as an optional GPU upgrade for the 2006 to 2008 1st-generation Mac Pros. It is based on a chipset originally developed by ATI Technologies (which was acquired by AMD).

Description
The Radeon HD 3870 Mac & PC Edition is based on ATI's RV670 XT workstation graphics chip that was fabricated by TSMC on the 55 nm process. The GPU clock speed was 777 MHz, producing up to 497.3 gigaflops. It contained 512 MB of GDDR4 video RAM. The card features a port and two dual-link DVI ports capable of driving up to 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 single PCIe 2.0 x16 slot, and required an auxiliary power cable.

Support
The Radeon HD 3870 Mac & PC Edition included a driver installation CD-ROM that required a minimum of Mac OS X 10.5.2 (Leopard) or later. The drivers were built into Mac OS X 10.5.4 and later. Some Mac Pros running Mac OS X 10.6.4 required a Snow Leopard Graphics Update for improved stability, which was incorporated into Mac OS X 10.6.5 and later. The card was supported through macOS 10.13.6 (High Sierra). However, it does not support Metal, and as a result will not work with macOS Mojave (10.14) or later.