Yes, you read that right GDDR5, I did not know it even existed!
Model# 4870PE5512SB
PCI Express 2.0 support
800 Unified Stream Processors
256-bit memory interface
Direct X 10.1 / Shader Model 4.1 / OpenGL 2.0
ATI Crossfire X Multi-GPU Support
High-speed 128-bit-HDR (High Dynamic Range) rendering
Up to 24x Custom Filter Anti-Aliasing
ATI Avivo HD Video and Display Technology
Game Physics processing capability
Up to 24X Custom Filter Anti-Aliasing
Built-in HDMI with Multi-channel 5.1 surround audio
Support for the ATI Radeon DVI to HDMI adapter
Unified Video Decoder (UVD) for Blu-ray and HD DVD