Flashed it and testing, im not sure if im happy with it though, I may back flash to V14 again, after all im manually overclocking so the boost clocks fix doesnt bother me.
Either my FCLK is causing the system to crash at 1900mhz or my CPU is no longer stable at 4.375ghz, ive just backed it off to 4.35ghz to see if its stable there, but if it crashes out again, then its the FCLK and im going back to V14.
On a different note, im running the latest beta of HWInfo, on Bios V14 it was reading the voltages correctly, on this V15 bios, its not.
EDIT: Just passed 25 passes of IBT AVX standard without a crash at 4.35ghz, Ill have to give it 10 mins though to see if it decides to reboot itself, again, if it does its the FCLK, otherwise if its fine then the CPU was no longer stable at 4.375ghz.