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Topic: How to change voltage and mem clocks correctly on 6870? Getting bsod (Read 2918 times)

hero member
Activity: 535
Merit: 500
If anyone knows how to adjust voltage through 11.04 or Windows 7 I'm all ears.
ATI Tray Tools.

Download and install Rivatuner. Since it's an old utility, it cannot detect your cards. Download and run RBE. If it detects the installed Rivatuner, it will prompt you to authorize adding your cards device IDs to Rivatuner's list of supported devices.

Use Afterburner to set the core and mem clocks, disable auto loading of AB every boot. Close AB. Open Rivatuner, detect clocks and enable "Apply overclocking on Windows startup".

Your cards will now have the customized settings even after reboots.

I use this method on my 6870s with 960/134 clocks.

AB was based on Rivatuner but I don't why my mem clocks revert back to default after reboot even if I configured it to apply the modified clocks on startup. My cards also locks up my rig if I set mem between 319-415. Stable clocks are 133-318, 416-1100.
Thanks for the info, but I've no problems with changing voltage and mem with Win. I need linux on usb flash stick. So, thats why I need to know how to change voltage and mem in BIOS without getting bsod. Or theres any other alternatives for Linux, some apps for changing voltage at least which will work for 6870?
full member
Activity: 173
Merit: 100
Download and install Rivatuner. Since it's an old utility, it cannot detect your cards. Download and run RBE. If it detects the installed Rivatuner, it will prompt you to authorize adding your cards device IDs to Rivatuner's list of supported devices.

Use Afterburner to set the core and mem clocks, disable auto loading of AB every boot. Close AB. Open Rivatuner, detect clocks and enable "Apply overclocking on Windows startup".

Your cards will now have the customized settings even after reboots.

I use this method on my 6870s with 960/134 clocks.

AB was based on Rivatuner but I don't why my mem clocks revert back to default after reboot even if I configured it to apply the modified clocks on startup. My cards also locks up my rig if I set mem between 319-415. Stable clocks are 133-318, 416-1100.
sr. member
Activity: 472
Merit: 250
I have a powercolor 6870x2 and normal 6870 in one of my rigs. In windows I use 11.12 CCC with crossfire enabled and Sapphire Trixx to adjust the memory clock. In Trixx, slide the memory bar down, let it reset, drag, and repeat until you're at 300 or your desired memory clock is acquired. Minimize Trixx, start CGMiner, hit g, change settings, and you will see the memory clock as it is default. Hit M, type in 300, and you will see the memory and temperatures drop.

I can adjust the memory however I want with crossfire enabled, but if I disable it will only allow me to go 150 below core clock. With crossfire enabled I cannot adjust voltage through Trixx or CGMiner, but with it disabled, Trixx will allow me to move the voltage bar. Currently, I adjust the memory as I have heat issues inside the case with all of the cards running.

If anyone knows how to adjust voltage through 11.04 or Windows 7 I'm all ears.
-ck
legendary
Activity: 4088
Merit: 1631
Ruu \o/
See if this card is affected by the "minimum difference" issue that 6970 has as well. Try setting memory to only 125 lower than the engine speed. If that works, try using the --gpu-memdiff -125 option in cgminer.
hero member
Activity: 535
Merit: 500
I have a Saphire 6850 @ 850/260 using CGMiner hashing away at 234MH/s. It's a bit sensitive to temperature and will crash over 72C, but it's running OK. I'm using Lubuntu 11.04 64bit.

Edit: I did have the memclock set at 260 but now it's stuck at 1000. I've rebooted 3 times attempting to get back to 260 or 300 and it refuses me. Maybe I should try 800 on the engine and try to alter memory again, we'll see.
It will always revert back to default mem clocks. And what about voltage, can you change it on Linux?
full member
Activity: 196
Merit: 100
Web Dev, Db Admin, Computer Technician
I have a Saphire 6850 @ 850/260 using CGMiner hashing away at 234MH/s. It's a bit sensitive to temperature and will crash over 72C, but it's running OK. I'm using Lubuntu 11.04 64bit.

Edit: I did have the memclock set at 260 but now it's stuck at 1000. I've rebooted 3 times attempting to get back to 260 or 300 and it refuses me. Maybe I should try 800 on the engine and try to alter memory again, we'll see.
hero member
Activity: 535
Merit: 500
 Nope, it's not possible for 6xxx series. Can't change voltage, or ram to 300 mhz with CGminer. Only gpu clocks are working.
full member
Activity: 196
Merit: 100
Web Dev, Db Admin, Computer Technician
Why change anything by flashing when you can make all of those changes with CGMiner?
hero member
Activity: 535
Merit: 500
 So, I just changed mem clocks to 300 mhz and voltage to 1.051 with RBE and getting bsod on windows load. Reflashed back to original bios. Any ideas what's wrong with it?
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