6950 memory downclock using Ati Tray Tools

[e21]

Sorry if this has been discussed already, I tried searching the forums and found some useful information, but not enough:

I just bought two Gigabyte 6950 1GB and unlocked the shaders; now I am trying to get them to run at 900MHz core or more, while downclocking the memory..

My problem is that whenever I try to bring the memory a single MHz below 775, it jumps to 1250, which is about 15 watts per GPU.
I have found topics related to this where people said they used ATI Tray Tools to downlcock the memory to 300MHz in Windows and verified using GPUZ; however when I tried installing ATI Tray Tools (using all default options), I go to 'Overclock', and the downclock limit for memory is 1000MHz, or if I go to 'Overdrive5' and try to bring memory below 775MHz, it jumps up to 1250MHz.

Are there some custom settings that will allow me to do this in ATI Tray Tools? I saw an option to switch from hardware to software overclocking mode for 'some unsupported boards', and anther option to enable or disable shared memory. I don't really know what I'm doing here, I've never used ATT before, any help would be appreciated!

Note: I have tried Sapphire TriXX and MSI afterburner unofficial overclocking, all with same results, memory jumps to 1250 if I go below 775MHz memory, or over 900MHz core. I am using Catalyst 12.1 WHQL with 2.5 SDK running Windows 7 64bit.

[1714783931]

1714783931

[1714783931]

1714783931

[1714783931]

1714783931

[e21]

Sorry if this has been discussed already, I tried searching the forums and found some useful information, but not enough:

I just bought two Gigabyte 6950 1GB and unlocked the shaders; now I am trying to get them to run at 900MHz core or more, while downclocking the memory..

My problem is that whenever I try to bring the memory a single MHz below 775, it jumps to 1250, which is about 15 watts per GPU.
I have found topics related to this where people said they used ATI Tray Tools to downlcock the memory to 300MHz in Windows and verified using GPUZ; however when I tried installing ATI Tray Tools (using all default options), I go to 'Overclock', and the downclock limit for memory is 1000MHz, or if I go to 'Overdrive5' and try to bring memory below 775MHz, it jumps up to 1250MHz.

Are there some custom settings that will allow me to do this in ATI Tray Tools? I saw an option to switch from hardware to software overclocking mode for 'some unsupported boards', and anther option to enable or disable shared memory. I don't really know what I'm doing here, I've never used ATT before, any help would be appreciated!

Note: I have tried Sapphire TriXX and MSI afterburner unofficial overclocking, all with same results, memory jumps to 1250 if I go below 775MHz memory, or over 900MHz core. I am using Catalyst 12.1 WHQL with 2.5 SDK running Windows 7 64bit.

SOLVED! - Sort of. I found a setting to remove the limit for overclock/underclocks under Tools & Options > General Settings > Advanced > Overclock limit

I am now able to downlcock memory to 300 while upping the core to 920 (and higher hopefully!), however that is only GPU 0, I have two 6950's in my system and two 6570 (soon to be replaced), how can I select the other GPUs in my system from ATI Tray Tools?

Note: something odd, when I go to Overdrive5 only GPU 0 is listed...

EDIT: on the bright side, GPU 0 is now happily running at 930 core/225 memory.. Something noteworthy: MH/s starts to drop pretty quick once memory is taken below 225MHz

[kpriess]

If those cards are not plugged to any monitors, or using dummy plugs at least, they won't be detected; that is probably your problem..

[TheHarbinger]

If those cards are not plugged to any monitors, or using dummy plugs at least, they won't be detected; that is probably your problem..

Haven't needed dummy plugs since like 1984.  Well not quite that long, but you don't need to Xfire or dummy up anymore.

[e21]

I've been trying to downclock the memory on my 6950's. I just can not get it below 1250 at all. I have tried multiple software's. I have heard of others flashing bios with lower memory clocks. It wont boot if I change the memory clocks lower. I saw this and have tried downclocking with it. Gpuz says the memory is clocked lower but when I run something, its graphs show it is running at 1250. So really, it did not downclock.

Did you really get it to downclock? I can post screen shots

Yes I'm sure I did; confirmed using GPU-Z and HWmonitor, also makes about 7-9 Watts per 6950 difference at the plug.. What brand 6950 do you have? It may be a BIOS limitation, in which case you can try flashing a differant brand 6950 BIOS which you can download from Tech Power Up http://www.techpowerup.com/vgabios/ NOTE!: Make sure to save your old BIOS first on to a flash drive that is formatted to boot atiflash http://www.techpowerup.com/forums/showthread.php?t=57750

Also I got the core voltage down from 1.175 to 1.05 while overclocking it to 910MHz at the same time   also verified using GPUz and HWmonitor

[Gabi]

I've been trying to downclock the memory on my 6950's. I just can not get it below 1250 at all. I have tried multiple software's. I have heard of others flashing bios with lower memory clocks. It wont boot if I change the memory clocks lower. I saw this and have tried downclocking with it. Gpuz says the memory is clocked lower but when I run something, its graphs show it is running at 1250. So really, it did not downclock.

Did you really get it to downclock? I can post screen shots

You have to use msi afterburner (of course with the modify to the conf file about the eula thing "i know what i am doing")

You start it, set memory at like 625mhz wich is the minimum and press apply.

You quit msi afterburner and reopen it. Now you will be able to go down to 310mhz. Set it and press apply.

[cypherdoc]

I've been trying to downclock the memory on my 6950's. I just can not get it below 1250 at all. I have tried multiple software's. I have heard of others flashing bios with lower memory clocks. It wont boot if I change the memory clocks lower. I saw this and have tried downclocking with it. Gpuz says the memory is clocked lower but when I run something, its graphs show it is running at 1250. So really, it did not downclock.

Did you really get it to downclock? I can post screen shots

You have to use msi afterburner (of course with the modify to the conf file about the eula thing "i know what i am doing")

You start it, set memory at like 625mhz wich is the minimum and press apply.

You quit msi afterburner and reopen it. Now you will be able to go down to 310mhz. Set it and press apply.

Why doesn't this work for me?

[mig91]

I've been trying to downclock the memory on my 6950's. I just can not get it below 1250 at all. I have tried multiple software's. I have heard of others flashing bios with lower memory clocks. It wont boot if I change the memory clocks lower. I saw this and have tried downclocking with it. Gpuz says the memory is clocked lower but when I run something, its graphs show it is running at 1250. So really, it did not downclock.

Did you really get it to downclock? I can post screen shots

Yes I'm sure I did; confirmed using GPU-Z and HWmonitor, also makes about 7-9 Watts per 6950 difference at the plug.. What brand 6950 do you have? It may be a BIOS limitation, in which case you can try flashing a differant brand 6950 BIOS which you can download from Tech Power Up http://www.techpowerup.com/vgabios/ NOTE!: Make sure to save your old BIOS first on to a flash drive that is formatted to boot atiflash http://www.techpowerup.com/forums/showthread.php?t=57750

Also I got the core voltage down from 1.175 to 1.05 while overclocking it to 910MHz at the same time   also verified using GPUz and HWmonitor

I have twin frozr II and III 6950's. I have flashed unlocked shader bios for the tw2 and unlocked ccc bios, because the shaders wouldn't unlock, for the tw3. So the cards are flashable. I have been trying to edit the bios using RBE to make the memory clocks go down. If I change the memory clock at all the card wont boot into windows and I get a bluescreen saying atimdag.sys. The driver doesn't like it or something.

I am going to play around with atitray tools a little more. See if I can get it to work. Maybe search for an already made bios on techpowerup instead of making my own.

hi! i have same problem that u have. im using sapphire 6950 1gb cards in crossfire and i cannot downclock the memory at all. if i use atitraytools i get bluescreen..
so did u solve the problem? i think i change the vbios to other, but i dont have any experience of that

[-ck]

Again, you are limited to setting the memory to 125 lower than the engine clock speed without 1. A bios flash OR 2. The right magic program that happens to know how to override this.

[mig91]

I cant even set it 10 lower. It says it is but runs at no lower than 1250. Its my card not the program

what brand is ur 6950?

[ewhenn]

To my knowledge it's a BIOS limitation on the card.  If you edit the BIOS on the card it will go lower.

My 6950 is locked so the memory can only be 125 MHz slower than core speed, anything less than that and it goes back to 1250.

[mig91]

To my knowledge it's a BIOS limitation on the card.  If you edit the BIOS on the card it will go lower.

My 6950 is locked so the memory can only be 125 MHz slower than core speed, anything less than that and it goes back to 1250.

can i edit bios with RBE ?

i have two 6950 1gig sapphires: http://p.gzhls.at/8710/658710/658710-1.jpg

[Gabi]

I've been trying to downclock the memory on my 6950's. I just can not get it below 1250 at all. I have tried multiple software's. I have heard of others flashing bios with lower memory clocks. It wont boot if I change the memory clocks lower. I saw this and have tried downclocking with it. Gpuz says the memory is clocked lower but when I run something, its graphs show it is running at 1250. So really, it did not downclock.

Did you really get it to downclock? I can post screen shots

You have to use msi afterburner (of course with the modify to the conf file about the eula thing "i know what i am doing")

You start it, set memory at like 625mhz wich is the minimum and press apply.

You quit msi afterburner and reopen it. Now you will be able to go down to 310mhz. Set it and press apply.

Why doesn't this work for me?

I have no idea, it works here, msi afterburner is the only thing that allow me to underclock the memory. CGMiner, trixx and others just don't work