Arroyo, I explained a bit the special settings in 2.42B on this post.
Try these:
*Droop Adjust: 1/4
*OVP - 250mV (default)
*PSI_EN - Disabled
*PSI_A - Two Phase (no matter what you choose, if you have PSI_EN disabled)
*DPM Setting - Disabled
*VCore Offset - 0.05V
PSI options and DPM relate to IC phase management (all disabled to oc), so the only relevant options are the other three (Droop, OVP and VCore offset).
*Droop Adjust: 1/4
This is the slope of the dropping voltage when load finishes, I think. Maybe slope in raising voltage too. If I disable droop adjust, cpu freezes on the beginning of load.
1/4 raises voltage more on load than 1/2, don't know the exact function though.
*OVP - 250mV (default)
Over Voltage Protection. Maybe board won't let Vcore above (Vcore set in bios + OVP) no matter what.
*VCore Offset - 0.05V (Vcore increase from that set in bios when CPU is full loaded).
The only thing with 2.42B is that it enables CnQ on reboot, but not on initial boot. 2.51 fixes that.
So then,
- NB voltage is CPU-NB that has to do with IMC and NB frequency (memory system) stability ?
- mGPU voltage has to do with FSB and onboard GPU stability ?
I improved my ram timings yesterday lowering them to 1806-8-9-8-24-1T from 9-9-9-24-1T. You should try 1T if you haven't, it's faster than 2T. Put them also on the two slots farther from the CPU, it helps.
I don't remember well if I tried memory voltages lower than 1.6V but 1.35V for my mem is for 1600-7-8-7-24-2T and i'm running them at 1806-8-9-8-24-1T...
Maybe I should try isolating components to test each component limit for overclocking, though you can do that better with a BE cpu. I think you should do the same, try to leave all things you can at default settings except memory, for example. Only thing is that to oc memory you have to raise fsb...
Maybe I should try again 2.51 raising mGPU voltage.
I hope Asrock releases new bios also for 890GX Extreme3 and 880G.