A forum member at 3Dcenter has posted what appears to be a legit Cayman/Antilles spec slide and several additional slides have appeared on a Polish tech site. All slides pretty much confirm what we already knew, but there are some new figures and surprises as well.
Cayman should pack 1920 stream processors in 30 SIMD engines, which proves that it’s a 4D architecture as expected. Computational power in single precision is estimated at 3 TFLOPs and the card boasts 96 TMUs, 32 ROPs and a memory bandwidth of 160GB/s. It will pack 2GB of 256-bit memory.
The Antilles features two Cayman GPUs and has a total of 3840 stream processors, 4GB of memory and a bandwidth of 307.2GB/s. The TDP for the Antilles is 300W, which doesn’t sound too bad considering the spec. Interestingly, the board won't feature native HDMI output, as it will pack two DVIs and three mini-Displayport outs.