AMD today released Pitcairn, the Radeon 7800 series GPUs. Radeon HD 7870 Gigahertz Edition and Radeon HD 7850 graphics cards complete the line-up of single GPU Southern Islands graphics cards. The Radeon HD 7870 has 20 Compute Units (CU), while the HD 7850 has only 16, giving them 1280 and 1024 Stream Processors (SP) respectively.

Built on a 28nm process and using the new GCN core Pitcairn fills the middle ground for price/performance with the HD 7870 clocking in at 1 GHz, and the HD 7850 clocking in at 860 MHz. Both cards come with 2 GB 128-bit GDDR5 memory in the standard configuration, running at 1200 MHz (effective clock 4800 MHz). This gives 153.6 GB/s maximum memory bandwidth. Both GPUs are listed as having a theoretically maximum Single Precision Compute Power of 2.56 TFLOPS, not bad for high-end mainstream cards.

HD 7870 has 20 CU (1280 SP) and 80 Texture Units. There are also 128 Z/Stencil ROP Units and 32 Color ROP Units. HD 7850 has 16 CU (1024 SP), and the same ROP configuration as HD 7870.

Both cards have a PCI-E 3.0 x 16 bus interface, making them ready the imminent release of Ivy Bridge. They offer full support for OpenGL 4.2 and DirectX 11.1, as well as AMD's own Eyefinity multi-display technology, with support for up to 6 displays. AMD App Acceleration brings OpenCL and Direct Compute to the picture, with support for double precision floating point calculations.

Radeon HD 7870 is available from $349, and Radeon HD 7850 from $249 at your favorite retailer.