Sapphire is adding a pair of new graphics cards to its line of the HD 7700 series based on the Graphics Core Next architecture from AMD. Both cards are built using a 28nm manufacturing process with 384 stream processors and clock speed of 800MHz. The main difference between the two models of HD 7730 GPU is in the memory, with one card featuring 1GB of DDR5 running at 4500MHz and the other with 2GB of DDR3 at 1800MHz. Both cards give the option to output to HDMI, DVI, and VGA with support for dual monitors and CrossFireX.
Source: Press Release