Strange Radeon HD 7970 memory underclock issues

[kallisti5]

Running a HD 7970 for mining, having some strange memory underclocking issues...

At load I get the following:

$ aticonfig --odgc
Default Adapter - AMD Radeon HD 7900 Series
                            Core (MHz)    Memory (MHz)
           Current Clocks :    1100           1375
             Current Peak :    1100           400
  Configurable Peak Range : [300-1125]     [150-1575]
                 GPU load :    99%

Notice how the memory peak is set to 400, but it still jumps up to 1375?

I get the same result no matter what memory frequency I set (400,600,800,1000,etc)

Thoughts?

Running Catalyst 12.8 under linux.

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[GernMiester]

For whatever reason (i have never bothered to look into it) if my core clock is set too high, my vram settings have no affect.
The VRAM goes right back to stock settings only slowing the core clock down makes it work.

[kallisti5]

Hmm good call..  it seems going over 950 Mhz gpu forces the memory clock from 800->1375

Strange... i swear I used to be able to underclock the memory to 600 while keeping the gpu at 1100

[squid]

I have the same issues with a Memory lock on my 7950 (max underclock is -150 Mhz of whatever GPU clock is). They are some forum posts throughout here and on guru3d talking about trying to unlock it, but I couldn't ever get it work.. not sure if its because these are a newer generation of cards or I simply cannot follow directions D:

[crazyates]

Using ADL (which is what CGMiner and most non-unofficial overclocking methods various programs use) cannot set the memory speed lower than 150MHz lower than the core. At 1100MHz, I can only set the mem to 950. At 1180, I can only go to 1030 for the mem.

Solution is to use MSI AB, with unofficial overclocking. I have mine set to 375 right now.

[kallisti5]

Thanks for the tips... i found the lowest memory and highest clock I could run on the 7970 without the memory jumping.


kallisti5@eris ~ $ aticonfig --odgc

Default Adapter - AMD Radeon HD 7900 Series
                            Core (MHz)    Memory (MHz)
           Current Clocks :    1100           950
             Current Peak :    1100           950
  Configurable Peak Range : [300-1125]     [150-1575]
                 GPU load :    98%

kallisti5@eris ~ $ aticonfig --odgt

Default Adapter - AMD Radeon HD 7900 Series
                  Sensor 0: Temperature - 85.00 C


I do wish I could get the memory clocks a little lower... but for now it's fine.   I moved to cgminer and am getting 650Mh/s which isn't *too* bad.


Thanks for the assist.

 -- Alex

[drlukacs]

This threat is somewhat old, but I am wondering if there are any updates on this topic.