G80 more details from R600

R600 came out finally. But, only a middle-end one can be ordered now. The reviews (1, 2, and etc.) didn't show much advantages over NVIDIA's G80. NVIDIA also came out a FUD presentation. It is quite interesting to read the presentation and it reveals more details of G80 and R600.

1. G80 has one special function unit per ALU, which is never documented or showed in any presentation from NVIDIA and manuals of CUDA.
2. R600 is a super-scalar VLIW architecture, which is different from R580 design and uses 5 scalar units instead of 1 vector unit and 1 scalar unit. That is an evolution step to the architectures used in GPU. The analysis on super-scalar VLIW architecture is fair to claim the efficiency issue. But, G80 is not a true scalar architecture, it's still kind of vector processor and also efficiency issue (and, yes, from somewhat different perspectives.) But, with compiler improvement, R600 will have more advantages if latency is critical to the computation.
3. It is reported that R600 is a cache heavy design, most of die size is devoted to SRAM. Beside texture cache and vertex cache, R600 has additional read/write cache to virtualize registers. This will benefit GPGPU (depending on the configuration of that read/write cache.) If such a read/write cache is "real" cache, that will improve the programmability and performance of R600 compared to CUDA on G80. The ever increasing complexity of graphics workload and GPGPU popularity has created demands on memory hierarchy for GPU. R600 may be optimized for stream computing.