MSI Afterburner: lowering CPU freq below 400 MHz?

[scooper22]

Hi there,

my card (Sapphire reference 6950 2 GiB 21188-00-40R) has 2D clocks of (stock) 250 MHz core and (stock) 150 MHz memory and runs at a modified voltage of 0.790 V.

I'd like to lower the frequencies even further but don't want to narrow down the minimum frequencies by flashing the BIOS over and over using RBE. Also i'm not sure if the driver checks 2D clock speed modifications as it does with 3D clock modifications and then prevents bootup when non-stock frequencies are found.

Therefore I'd like to tweak the clock speeds using MSI Afterburner - but the program's sliders have a minimum value of 400 MHz core and 625 MHz memory.

a) why the heck is there a lower limit anyway and why is it way over the default frequencies?
b) more importantly: How can I modify the lower limit of these sliders to have some room for improvements?

Thanks

 

[erocker]

http://www.techpowerup.com/forums/showthread.php?t=117633

It should work for 3d settings as well.

 

[m&m's]

http://www.techpowerup.com/forums/showthread.php?t=117633

It should work for 3d settings as well.

It works, I've tried it. But there is a limit, with my HD 5770 I could not set lower than 80MHz core clock and 150MHz memory clock. If I set 79MHz or lower for the core clock it was just doing nothing and it's the same for 149MHz or lower.

But with TRIXX there is no limit. I was able to set to the lowest possible until artifact appeared witch was 70MHz and 140MHz.

 

[scooper22]

ah, thanks for giving me the direction!

I have only the basic display drivers and APP installed but skip CCC as I think it's kind of bloatware.

a) isn't there a way to achieve this without CCC? I've never used it for anything
b) alternatively point me to some reasons to actually use CCC

Trixx seems like it's out as it looks like it can't switch between 2D/3D clocks and has no OSD

 

[m&m's]

You edited your first post, when I replied there was no mention about 2D clocks!

a) Maybe but I don't know an other way.

b) The application profiles. That give some performance boost even if not in CrossFire.

 

[scooper22]

I gave CCC (AMD VISION) a try and was able to lower 2D core clock to 126 MHz and 2D mem clock to 80 MHz, every value below these had no effect and were ignored. The system is stable with these low settings and no practical impact observable (feeding a 1920x1200 display over a dual-link DVI-D is no problem: no gfx glitches, no stuttering or decreased display speed)

However changes to the CoreVoltageTarget_* were simply ignored and the voltages taken from the BIOS Powerplay state voltage definitions.
Is there something I'm missing to enable voltage regulation through CCCs profiles?

Running driver 8.982-120727a-144945C-ATI (official 12.8)

 

[scooper22]

- fiddling around with CCC and AB led to nothing
- reflashing original BIOS just made the default BIOS voltages become active but CCC does still not apply the want_ voltages
- I found this: "Control Center 11.7 Released [...] Voltage control stopped working" - any insights?

still amazed and slightly puzzled about the low and flawless 126/80 (core/mem) frequencies (confirmed by GPU-Z and AB) and why 80/150 is the lowest setable for m&m's..


addition:
- using 12.8 driver with 12.6 CCC did not enable voltage control
- interesting: the lowest clocks with this combination are 125/75, so an additional little but lower


addition 2:
- deinstalled 12.8 completely, ran driver sweeper, installed 12.6 driver and CCC
- core/mem clocks can be changed; voltage not, still BIOS values

 

[scooper22]

okay, got rid of CCC again. It's not worth the disk usage and clutter and uses CPU cycles... what for?

thanks for all the help at this topic. Back to bare drivers, Afterburner for OSD and monitoring (overclocking currently unused) and fan control with speedfan