You can read continue to read this as a guide but this is a better tool IMHO.
I chanced upon this site : http://amd.goexchange.de/
The program is free for home users (However you are encouraged to donate as it is a lot of work) and it is not free for business users
In short conserve power (Battery Life) and reduce thermal emission (Overheating) with no effect on Computing Performance for more info check on the previous link.
2)For Intel Processors and AMD TL and older Series Mobile Processors RMClock is able to overclock them.
However no tool was available to underclock CPU until this tool was release.
How to use?
The documentation on the site is very lengthy and rather confusing.
I was confused first time I read it.
A very simplified guide as follows:
1) Create a folder in Program Files.
eg. Create C:\Program Files\GriffinControl
2) Download the files required (scroll down a bit you should see 2 files each for 32bit and the other 2 files for 64bit) and extract them to the folder you created in 1).
3) Open the GriffinControl_config.xml with notepad (the author provided a skeleton configuration file) .
You will only be looking at the following column and the values in bold
How do you go about setting voltage?
Basically AMD ZM/RM Series Processors has 3 Power State.
A full state runs at max frequency when you need the processing power it throttles up to maximium frequency giving you the computation power you need.
This is pstate number 0 which is 100% of the total CPU Power.
pstate number 1 is 50% of the total CPU Power.
pstate number 2 is 25% of the total CPU Power.
If you set too low a voltage the CPU will not run stably due to unsufficient voltage and cause BSOD.
For QL/SI Processor you only have 2 pstate, 0 & 1.
pstate number 0 which is 100% of the total CPU Power.
pstate number 1 is 50% of the total CPU Power.
How do you know the default voltages for the CPU?
Either you run CPUZ as shown by the picture at the end of this entry.
Then use Vista Processor Power Management to throttle at different percentages to find the 3 or 2 voltage level depending on what processor you have.
If you are not sure you can leave a comment at the end of this entry I will recommend values for you to try.
Another way is to refer to the config file provided with the downloads.
4)Reference this table for the list of Voltage ID.
eg. The value 42 as shown above translate to 1.025V and so on.
(Note the lowest VID is 64 no lower values will work and value above 36 can fry your processor )
Edit the values to the voltage you want.
For my RM-72 Processor, I tested 64,52 and 42 is the most extreme stable values.
Which translate to: 0.750V, 0.900V and 1.025V respectively.
Original Voltage: 0.800, 0.950V and 1.075V respectively.
A difference of 0.05V, 0.05V,0.05V , any higher it BSODS
Change the values accordingly and save.
6)Run GriffinControlService_32bit.exe for 32bit Windows and GriffinControlService_64bit for 64bit Windows.
Follow instruction and create the Windows Service if you encounter an error message you did something wrong.
Go to Services Menu and Start the Service if you ever want to delete the service you must stop it first (using the same manner, stopping it instead of starting it)
If you are doing testing make sure the service is set to manual start instead of Automatic so after BSOD it will default to original value and not BSOD repeatedly I learned this the hard way.
If you did not listen to me and it BSOD repeatedly, when it is possible to get to Windows Either start with last saved configuration or try to switch to Power Saver Mode in Vista Power Plan so it will not cause BSOD again.Don't worry no physical damage is done to the processor.
7) Run a CPU stressing Tool like Intel Burn In make sure no BSOD happens when running the tool so the voltage is stable. Use the Vista Processor Power Management to test the different Power States.
Set to auto start service if you are happy with the final setting.
This program is very well created especially when the author implemented it as a windows service, so donate to the author if you are able to.
Special Thanks to the author, now my CPU Voltage Temperature Dropped by a lot at max frequency.
Proof that it works!
Edit: The Service hung on Vista and created a Windows Event Log (no error message) so I set it to Delay Start and the problem went away.
At the end of the process the result of undervolting implies AMD chips are indeed overworked in order to catch up to Intel Processor Performance, the undervolted amount of 0.05 at max frequency implies this.
Any further undervolting results in BSOD.
Just encountered another BSOD raise voltages by 0.025
Finally whenever you encounter a hardware BSOD (read the message on the BSOD) just raise the voltage by 0.025.
Eg. when you BSOD on youtube you probably need to raise p-state 1 and p-state 2 by 0.025
My guess is when the CPU changes state from 2 to 1 it switches too quickly therefore insufficient voltage to support the boost hence it BSOD.