RBE overclocking - unable to change default voltages

[SoulsCollective]

Hey folks
Card in question is a Sapphire reference 5870, standard 850/1200 clocks. Bought it in the very first week of Australian release.

I'm trying to push past 920 core, which is stable on stock volts, but can't seem to get voltages to change from their default values. Changing clockspeed and fan settings works fine, it's just voltages that I'm having issues with. I'm using RBE 1.25, but no matter what I change the 0x18 register to GPU-Z still shows a load voltage of 1.125V. I've tried putting values of up to 1.5 for each register, but neither the idle or load voltages change - they're stuck at 1.065 and 1.125 respectively. However, if I use MSI Afterburner to try and set a custom core voltage I have no problems - Afterburner can view and change max core voltage without issue, with the changes confirmed by GPU-Z.

Any ideas? I've tried a Google and come across multiple threads on other forums on the issue (see eg. here over at TPU where BAGZZlash admits he has no idea), and noone seems to have any solutions - if the stock volts of your 5870 are 1.125, you seem to be stuck with that value.

I know I can always hard-mod my card, but I'd really rather not if at all possible, so I'm hoping someone here may have an idea on how to fix this.

[Pedropc]

To me it's the same with my 5850 reference, I can not change the voltage (1.125 V), ?????

[japamd]

MSI AB can overvolt it ?

[Musho]

Try resetting to factory defaults after flashing your card by doing this:



That should force CCC to reload the bios values.

[Pedropc]

No, does not work with MSI AF, two are reference model, two with identical bios flashed , one voltage change (1.1625 V) and the other not (1.1250 V), a greeting.



Uploaded with ImageShack.us

Sorry for my bad English.

[SoulsCollective]

MSI AB can overvolt it ?

Nope, AB just has greyed out fields for both core voltage and shader clock.

Edit: Doh! Goes to show I've never used AB before - I'd forgotten to unlock voltage control. Yes, AB can change core voltage, as with the linked TPU thread - I just can't flash a custom BIOS with those settings.

Try resetting to factory defaults after flashing your card by doing this:

*pic snip*

That should force CCC to reload the bios values.

Haven't tried that, but have tried uninstalling all ATi software, running Driver Sweeper, and re-installing - which should accomplish the same thing.

[japamd]

Nope, AB just has greyed out fields for both core voltage and shader clock.

Edit: Doh! Goes to show I've never used AB before - I'd forgotten to unlock voltage control. Yes, AB can change core voltage, as with the linked TPU thread - I just can't flash a custom BIOS with those settings.

Haven't tried that, but have tried uninstalling all ATi software, running Driver Sweeper, and re-installing - which should accomplish the same thing.

Try dumping your current bios, edit it using RBE and flash it back.

Edit: your RBE screen looks like this?


The voltage of Clock Info 00 is "---" ? Maybe you could try putting the stock voltage value there, then edit the 0x18 field of GPU registers.


Different card, but FYI RBE looks like this here:


Maybe it works if you change voltage of clock info 00 to your 3D stock voltage (1.125)

[SoulsCollective]

Try dumping your current bios, edit it using RBE and flash it back.

Tried that. I've tried every 850/1200 reference series Sapphire BIOS hosted on TPU, on none of them am I able to change voltage.

Edit: your RBE screen looks like this?

No. My 0x18 register is, by default, 1.175 - although this still results in a load voltage of 1.125.

The voltage of Clock Info 00 is "---" ? Maybe you could try putting the stock voltage value there, then edit the 0x18 field of GPU registers.

Default is ----, yes, and I've tried inputting values directly into that field - again without success.