Hi. I think i kind of found a bug. The main thread of this bug is this one (link in front), and i've read in the page 8 of this topic some other users experiencing the same problem:
http://www.techpowerup.com/forums/showthread.php?t=153587
I Will resume what i consider to be the bug in here for your convenience.
Well, I've tried to apply to my card the following settings:
Clock speed: 950 Mhz
Memory Speed: 1270 Mhz
GPU Voltage: 1.200V
Memory Voltage: 1.167V
Bios: Asus HD 5870 (i got the V1 card, reference one, 1 GB)
However, after the flash, GPUz could only read 1.125V on the GPU Vcore. I know this isn't a GPUz read error because as soon as i press "stress test" on GPU Tool my screen gets all striped up (and the same profile is stable under MSI Afterburn).
Now, i think this is a bug in the 0x18 register (or maybe it is just a lack of support for other per discover register) because, if i change the other values (the idle one, or all of the VTT (memory) ones, they get applied correctly.
Could there be some other register hidden in the Bios?
The only odd thing is that if i open MSI afterburn, and without any overclock on the program applied, if i press "reset", the voltage on load jumps to 1.167V (the same voltage RBE claims to be the default on register 0x18, in the backup of the untouched bios.
Thank you for your time, i hope this can be figured out. This program is actually very handy and simple to use, thank you for creating it
EDIT: What about the drivers? I think they can too force voltage on the card. Could they be somehow detecting that this card can run flawless @ 1.125V and override the Bios settings?
EDIT2: If it is the driver, its included in them since ever. I downloaded the first driver ever released to HD5870, installed a fresh windows in another partition and it still loads @ 1.125V. So, Guess its a road with no exit since BAGZZlash doesn't know whats happening here. Can it actually be something that was not well documented and thats why we can't find it easily (that supposedly "undiscovered / nonexistent" register)?
Final Findings:
Well, for resume after a really long testing i can only get into this two way dead end:
Card: HD5870 Asus 1GB
A) The driver is forcing the voltage, and they need to be moded somehow in order to let the Bios settings come up.
BUT: This isn't probably the case because, if it was the case, after we press "Reset" in MSI Afterburn, the value should return to 1.125, but instead it returns to 1.1675 (GPUz Measurements), and should return to the BIOSs personalized voltage.
B) There might be something missing in AMDs Documentation, thus making us not find the "missing Register" that contains the actual real load voltage in this "Cherry" cards that where shipped @ 1.125V, and thats why BAGZZlash can't figure out what's wrong.
I Excluded the possibility of "we can't change it because its locked" since i can change the voltage perfetcly fine in MSI Afterburn, and i can change all votlages (all VTT's and all GPU's Voltages exepet register 0x18) with success using RBE.
Thats the most far i could narrow this issue down, maybe someday this gets fixed