i haven't tried your bios but i made a custom one and tried it out,

voltage 1 and 2 set to 1.1v
voltage 3 and 4 set to 1v

this didn't help , my overclock on the core got worse, i haven't tried shaders

custom ram timings with default voltage: top-down, left-right,
40,52,30,16,16,12,12

it didn't help at all for the ram oc, looks like really crappy ram