VR Zone heard from Asian sources that the R600 GDDR3 card uses a 12-layer PCB while the R600 GDDR4 uses 12-16 layer PCB. Even more:
The silicon for R600 only reaches A13 revision and there are no A14, 15 or 17 revisions. According to them, currently all the ATi R600 benchmarks out there aren't real and R600 core clock is not lower than 800MHz. VR-Zone has learned about some updates on R600 availability. Apparently R600 GDDR3 will be available in early May while R600 GDDR4 will be available in mid May but in limited quantities.