Bitcoin Forum

Hi

I'm using MSI Afterburner to tweak my 2x6950 set up. I've used it to underclock my memory to 625Mhz...However, the MSI hardware monitor shows that the clock jumps back up to 1250 once I start mining. When idle, it shows the mem speed at 150Mhz (presumably the GPU is  in energy saving mode).  I know that Afterburner is doing something when I tweak my cards to 625Mhz since GPU-Z shows the change.

I've also tried Saphire Trixx, but that utility appears to be a bit buggy with my dual gpu setup.

Those that are underclocking your memory: does MSI's hardware monitor show your memory speed jump up when under load too? Anyone know how to keep mem speeds low while under load...or am I doing something wrong?

you prob have a non ref card like me and cant under-clock the memory with current applications available.

the jump up is the card switching between low power idle mode and full power 3d mode.

so in effect your underclocks aren't actually having any effect.


my cards are gigabyte 6950 oc's

use clocktweak (http://forum.bitcoin.org/index.php?topic=9982.0;all).

the 6950s have three levels of memory clocking: idle, some load, full load.
you need to set these levels individually for each card.

in this (http://forum.bitcoin.org/index.php?topic=9982.msg375979#msg375979) I lay out the procedure.

• is your adapter#

you will probably only get the GPU to 840 and the memory down to 800.

i guess ill have to buy it and try it...

ok so i admit i had my hopes up but still same thing, can clock up but not down ... ;(

above 1250 has effect, below it does not. 

clocktweak.exe -y -a 0 -m 1250


ive been able to underclock the mem only with racerX (same author as RBE) but the GPU becomes locked at 500, so no good either, but shows me there is some possibility of lowering the mem clock with these cards.

did you use this?


with my cards, i need to set the memlevels individually.

wow it actually worked (executing the 3 commands sequentially) omg! (except i imagine you ment -memlevel instead of --, and also level1 instead of 2)

but hey, ill give it more a go see how low i can get and the temp core oc differences and post back.  :D

please do! on my cards i can NOT go below 800.

edit: blunders fixed.

ok quick report on lower limit. 775 was as i could go b4 it just jumps back up to 1250. (more details later)

also i could keep executing just the last command by itself once the first 2 of 3 had been run the first times.

yes, sorry, that is true.

i have three batch files for my miners.

01 memory.bat

02 start.bat
since adapter 8 whatever reason gets hotter than the other two.

03 stop.bat

So when I am forced to reboot, I can just klick the first file, the next file, start guiminer. should i be forced to stop mining for a while, i will just turn down core clock and fans.

the -o 10 thing keeps a cmd window open and tells me the current status of the cards, every 10 seconds.

Dont give up before trying ati tray tools. That worked for me and now I can set gpu/mem clocks to anything. For some reason voltage settings doesnt work for me even with ati tray tools, but 6970's bios default(1.175v) is enought. Running my asus 6950 @ full shaders and 900/150 MHz.

Any idea how to do this in Linux?

Thanks

Get a list of your active card indexes:

Start up AMDOverdriveCtrl for each index.  Modify your core/memory settings and save it to a profile for each index (ie profile0.ovdr, profile4.ovdr).

Now create a shell script to enable the profiles for these card indexes:

The profilen.ovdr files are just xml tagged files.  Easy enough to edit them to tweak any changes without going back into the GUI.

Sometimes when I mess with the clocks in Afterburner on 58xx cards it does the same thing.

While the miner is working I:

1. Change the core clock up a little but up and the memory clock a little bit down
2. Click Settings, select a different GPU. Wait for the "GPU# Selected" to go away
3. Click Settings, go back to the trouble GPU. Wait for the "GPU# Selected" to go away
4. Clock up/down to the desired amount.

I'll go to like 600 or 700 memory, then I'll switch, come back, and go to 305.

This seems to do the trick. If I don't do this it just keeps switching back like what happens to you.

You can also try changing it in smaller increments and letting it run for a little bit each time you switch the speeds.

For a while my cards were real fussy about their memory being underclocked, then one day they all decided to play nice.

If this is a dedicated miner you should check out LinuxCoin: http://forum.bitcoin.org/?topic=7374.0

Follow this guide if you want to put it on a USB drive: http://forum.bitcoin.org/index.php?topic=7374.msg286940#msg286940

wow, thankyou so much ! id used atitraytools years ago. it actually works a treat ! after disabling clocking limits in advanced option i could go all the way down!

got down to 50mhz memory, and realised it was affecting my hash rate so i went back up to 200-300 where i still get full hash rate.
i will post more details about temperature difference and core oc advantage soon as i was going to with clocktweak but i wont be using that now....


thanks again !  ;)

yup! ati tray tools does it for me too. after adjusting the mem speed down in ATT, MSI's hardware monitor does indeed show the lower clock during load. my kill-a-watt also shows a nice drop in watts.

btw, i also tried AMDOverdriveCtrl under linux, but did not notice a decrease is power usage when I lowered my mem speeds.

well somehow i totally corrupted my CCC , and had to uninstall that bit to even start windows without it crashing with artefacts....

so no i just use atitray which is fine for the job instead.

going from 1250 to 405 mhz dropped my two cards from 78 to 73 & 74 to 69

and now i cant go 400 or less without it dying from artefacts and freeze.

but i run a bit higher around 450 as it actually lets me run a higher core clock.