Guys i think i may have been a little hasty with my summery of the jz bios, i decided to give it another go & did a fresh install. The thing is even though gb have adjusted the vdimm to better represent real vdimm this was not my long run prime stabiliry problem. What i have found partly due to not believing what im seeing combined with falkentyne's constant mention that jz is good & fixed his cold boot problem is jz kind of locks voltages & unless you psu power off after each change it wont register voltages properly in software & is therefore unstable. My board is now running fine on this bios.