This is a dump of aticonfig. Forgive the formatting.
ATI Overdrive (TM) options:
The following options are used to get and set current and peak, core
and memory clock information as well as read the current temperature of
adapters. By using the "--adapter=" argument the ATI Overdrive (TM)
options can be targeted to a particular adapter in a multi-adapter scenario.
If no adapter is explicitly targeted the commands will be run on the Default
adapter as indicated by the "--list-adapters" command
--od-enable
Unlocks the ability to change core or memory clock values by
acknowledging that you have read and understood the ATI Overdrive (TM)
disclaimer and accept responsibility for and recognize the potential
dangers posed to your hardware by changing the default core or memory
clocks
--od-disable
Disables ATI Overdrive(TM) set related aticonfig options. Previously
commited core and memory clock values will remain, but will not be set
on X Server restart.
--odgc, --od-getclocks
Lists various information regarding current core and memory clock
settings.
Including: current and peak clocks
the theoretical range clocks can be set to
the current load on the GPU
--odsc, --od-setclocks={NewCoreClock|0,NewMemoryClock|0}
Sets the core and memory clock to the values specified in MHz
The new clock values must be within the theoretical ranges provided
by --od-getclocks. If a 0 is passed as either the NewCoreClock or
NewMemoryClock it will retain the previous value and not be changed.
There is no guarantee that the attempted clock values will succeed
even if they lay inside the theoretical range. These newly set
clock values will revert to the default values if they are not
committed using the "--od-commitclocks" command before X is
restarted
--odrd, --od-restoredefaultclocks
Sets the core and memory clock to the default values.
Warning X needs to be restarted before these clock changes will take
effect
--odcc, --od-commitclocks
Once the stability of a new set of custom clocks has been proven this
command will ensure that the Adapter will attempt to run at these new
values whenever X is restarted
--odgt, --od-gettemperature
Returns the temperature reported by any thermal sensors available on
the adapter.
ACPI Options:
–acpi-services=on|off
Enable/disable ACPI services. In the case of BIOS or kernel ACPI issues,
ACPI services in the driver can be disabled through this option.
The ACPI services are enabled by default.
–acpi-display-switch=on|off
Enable/disable display switching with ACPI methods on mobile platforms.
This option is enabled by default.
My card – ATI Radeon 5770. Enable overclocking and show values:
sudo aticonfig --od-enable – Enable overclocking
sudo aticonfig --odgc – Show current card clock values
Output from my example card (ATI Radeon 5770):
Default Adapter - ATI Radeon HD 5700 Series
Core (MHz) Memory (MHz)
Current Clocks : 850 1200
Current Peak : 850 1200
Configurable Peak Range : [600-960] [1200-1445]
GPU load : 97%
Overclocking:
aticonfig --odsc=930,1400 – Set clockspeeds, in MHz [coreclock,memoryclock]
aticonfig --pplib-cmd 'set fanspeed 0 80' – Kick up the fanspeed
Foreverrising Blog 
not a chance to modify volts?
Comment by Tabris — June 10, 2011 @ 1:50 am
No, nor to underclock more like I see in Windows with MSI Afterburner. If I could get the memory clock lower than the 1050 I have it at, hashrates would go even higher.
Comment by foreverrising — June 10, 2011 @ 9:27 am
The configurable peak range of core of my 5770 is only [500-870], not as high as yours, is that normal?
Comment by cb — June 25, 2011 @ 7:45 pm
The range has to do with the voltage regulation of the model. For instance, the Gigabyte Radeon HD 5770 SOC (GV-R577SO-1GD), the super overclocked edition, ranges up to 1000MHz.
Comment by foreverrising — June 26, 2011 @ 9:00 am
Hello, I’m running Ubuntu 10.10 and I recently checked my configurable range. It said 750-750 on shader clock. I read about a guy who used MSI Afterburner to go past these limits so I was wondering if you know of any ways of doing that in Ubuntu? Thanks.
Comment by Nelson — July 4, 2011 @ 9:09 am
Each card allows for a different configurable peak range. Some are higher- like the black editions. Some are lower..
Comment by foreverrising — July 9, 2011 @ 8:29 pm
I find it hard to believe that so many (I’ve seen hundreds of posts) people has the problem in Windows that I am going to describe, but there is no fix for it in Linux.
My ATI Powercolor HD 5770, like many many others has a harware design problem. The default low clocks 157/XXXX cause garbled screen while switching to 400/XXXX or 500/XXXX and back, and most of the times the card freezes after a while. This happens with Windows XP, Windows 7, and of course, with my Ubuntu with ATI accel. driver.
In Windows, I can go to a specific config file for the Catalyst configuration and force the “minimum core and memory clocks” to 400/1200, instead of 157/XXXX (forgot how much is XXXX but it’s <1200).
But in Ubuntu, with aticonfig I cannot do it. I can set aticonfig -odsc 400,1200, yes, but that's only for the peak CLOCK, not for the default (minimum) clock.
So, I'm stuck !! And I have to quit writing because my screen is flickering and pretty soon I'm going to freeze.
Any idea for a solution ? The answer is not "dont use the accel. driver", because without it, my fan is going to run at 100% and it's simply too loud.
Comment by Pedro Lucas — October 11, 2011 @ 9:34 am
I’m not sure if this is the answer you’re looking for, but the only way I can change clocks outside the cards BIOS limits in Ubuntu is to run AMDOverdriveCtrl from Sourceforge. I open it up and minimize it to the taskbar and then -odsc will let me set the clocks beyond what aticonfig –odgc shows the limits are.
I hope this helps. If not, please rephrase your question. You’re downclocking, and not for mining right?
Comment by foreverrising — October 11, 2011 @ 10:30 am
Thank you for the fast answer. Meanwhile, I found AMDOverDriveCtrl too from a post (https://bitcointalk.org/index.php?topic=12035.0), installed it and changed the IDLE (I was calling it low clock but ofc it’s the called the idle clock) core+memory clocks from 157/XXXX->400/XXXX.
For the 5770, the core clock range is 157-850 (non-overclock), and I wanted to set it to 400, but I couldn’t, without AMDOverdriveCtrl, since aticonfig only changes the PEAK clock, not the IDLE one.
Now I have a non-flickering and a non-freezing card, without the core/mem clocks floating too much. All the blabla about why this happens (hardware) is posted on several forums since 2009 or so, when the first HD Radeons with this problem started to come out. I find it amazing that after all these releases (11.9 atm, I think), ATI/AMD still doesn’t understand what to do with the IDLE clocks for these chipsets/cards with this problem. They probably want to startup in a “powersaving” mode, but honestly….
AMDOverdriveCtrl is indeed the answer, now all is left is for me to try an set it automatically on each startup.
Hope this post helps others like me that want to have this card running Ubuntu outside Vmware.
Flickering screen ? Ubuntu ? HD Radeon 5770, 5870 or alike ? Get AMDOverdriveCtrl.
Comment by Pedro Lucas — October 11, 2011 @ 11:09 am
Yes, I searched out an answer to set the memory clock to its absolute minimum to lower its temperature while mining. I know changing clocks helps in other cases, like preserving laptop battery life.
Cheers
Comment by foreverrising — October 11, 2011 @ 11:26 am