Testing F4 final bios now.
It seems to be, again, quite an improvement over the beta bioses released earlier. Still the clock wall, though, limiting this chip to around 4800MHz on (crappy) air even with only two cores enabled. The BCLK overclocking capabilities have improved, giving me a perfectly functionaly 1.25x ratio! Really, no sweat pushing the BCLK anymore. Performance seems solid as well; here's a 4xCF run.
As you can see, there seems to be no Physics low bug on this one. Before I switched to the UD7, I did some runs on the R4E and my physics at similar clocks was around 14700. Now I sometimes get 15500.