Memory won't underclock with clocktweak on my "6970"

[slaithe]

I can't reply to the relevant thread because of my newbie restrictions, so here's hoping this reaches the right eyes.

I've flashed my reference Sapphire 6950 2GB to 6970.

ClockTweak thread
http://forum.bitcoin.org/index.php?topic=9982.msg143526#msg143526

My command line:
clocktweak -a0 -c900 -m300 -y
While GPU-Z (Graphis Card tab) and the -r show the Memclock at 300, GPU-Z (Sensors tab) and CCC show the Memclock at the default 1375.

I first noticed the problem when setting Memclock with clocktweak seemed to have no impact at all, while small differences were noticed with Coreclock adjustments.

Suggestions?  If I modify the BIOS and flash to 900MHz/300MHz settings, can I use CCC or clocktweak to switch between 880/1375 and 900/300, easily?  This is a brand new card and I do plan on gaming with it, too.  So I'd like to easily switch between mining and gaming without having to reflash/reboot every time.

EDIT: Catalyst driver version is 11.6 (11-6_vista64_win7_64_dd_ccc_ocl.exe).

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[fascistmuffin]

I know that MSI Afterburner, after unlocking it via cfg files, you can under/over clock to flashed settings. It also has 5 profiles you can save to. Might be an easier program to use rather than using cmd.

[slaithe]

Thanks.
Nice GUI app, but the lower Memclock limit is 1035. :/  I followed this post's directions to add the "EnableUnofficialOverclocking = 1" line, but it was a no go and I still can't go below 1035.  Did I miss something?

http://www.overclock.net/8592866-post2.html

EDIT: I was using v1.10.  Now using v2.1 and can go down to 685, but no further. :/

[slaithe]

Sorry to double post, but I thought my discovery of resolution warranted the bump since no one else in the newbie section has provided this info.

ATI Tray Tools worked!  I was able to set my clocks to 900/300 on my "6970" changed my command line for my phoenix miner using some of the info on the following wiki page.

https://en.bitcoin.it/wiki/Mining_hardware_comparison

So, I've gone from about 290Mh/s to 379Mh/s.   Nice big tweak! after a little more tweaking and a case upgrade to accommodate more airflow, maybe I'll hit around 400Mh/s.  I haven't even messed with voltages, yet.

[epg]

@slaithe: Thanks for the update when you found a resolution. I've just recently unlocked the shaders on my 6950 2gb (getting ~355mh/s @ 840gpu/1250mem), but I'm weary of flashing straight up to the 6970 bios because I read some other people mentioning the different voltages between the 6950/6970. I'll look into doing something similar after I do more research into it.

[Solution]

Whoa

[slaithe]

@slaithe: Thanks for the update when you found a resolution. I've just recently unlocked the shaders on my 6950 2gb (getting ~355mh/s @ 840gpu/1250mem), but I'm weary of flashing straight up to the 6970 bios because I read some other people mentioning the different voltages between the 6950/6970. I'll look into doing something similar after I do more research into it.

Unlocked just the shaders?  You find a BIOS for that or did you have to modify your own?
From what I understand, the original reference 6950s were just locked down 6970s, hence the term "unlock."

I haven't had any other difficulties with my "6970" now other than heat considerations since I kept my GTX 285 in so I can do Hybrid PhysX.  In addition, and this is an issue with AMD's drivers, I can't watch accelerated vids or game while the 6970 is mining, even if I'm using CUDA off the GTX 285 to accel the vid via CoreAVC.  As hackneyed as it is, I have to switch over my DVI cable to my GTX 285 and then everything is fine, as long as I don't have to restart the miner.  That requires I switch the DVI back, unless I just need to learn something else.  I'm not new to cmd by any means, but the switches/parameters change whenever I move the DVI cable from gpu to gpu.

All in all, I'm happy with my purchase of this Sapphire 6950.  I'm a gamer, so bitcoin is more of a side hobby, for now.  As it is, the GTX 285 runs most of my games to my liking so I can still game while mining and take mining offline when I want to play something more demanding or better detail (more AA, DX11, etc.)

EDIT: And this all probably means I'll be seeking a refund on the 0.2 BTC I spent to get clocktweak.
EDIT2: Another explanation I've read is the 6970s may have also been locked down to 6950s b/c they were too power hungry/wasteful when clocked up to 6970 speed.  No matter for me. I have 1000 watt PSU.