The card reportedly has 2GB GDDR5 memory and two RV870 GPUs clocked at 725MHz, which is 125MHz less than the Radeon HD 5870. The TDP is 294W and the theoretical computing performance is 4.64 teraFLOPS.
It will likely be the fastest graphics card of 2009, unless NVIDIA can squeeze out some desktop Fermi graphics cards before year-end.