If you're having issues OCing your 4850...

[krameriffic]

Try checking the stock core voltage. I just discovered that, along with the adjustable fan speeds in the different profile XML's, there is also an option to adjust core voltages (probably within a reasonable range). I couldn't get my 4850 stable over 650 core running with an Accelero S1 with a 120mm Scythe fan on it and sinks on everything. The autotune option in the CCC automatically brought up the core voltage for me, and now I have it stable at 700/1100.

The profile file is located in "C:\Documents and Settings\(Your Account Name)\Local Settings\Application Data\ATI\ACE" in Windows XP (not sure about it's location in Vista, check in the threads about the fan hack). The string in the XML file looks like this:

        <Feature name="CoreVoltageTarget_0">
          <Property name="Want_0" value="1046" />
          <Property name="Want_1" value="1046" />
          <Property name="Want_2" value="1158" />

The one you want to edit is the "Want_2" value="xxxx". This is the 3d voltage in millivolts. For me it was stock at 1083, and the autotuner brought it up to 1158. I have not noticed any significant increase in temperatures (maybe a degree or two) but it's actually stable now. The stock voltage has varied a bit from card to card from what I've read. This is saved into that particular profile, so make sure you load it in the CCC in order to achieve those settings.

The other values are probably the 2D voltages. Fiddle with this at your own risk.

 

[SilverSliver]

This was discovered a few weeks ago..

 

[krameriffic]

This was discovered a few weeks ago..

Apologies.. I never noticed it until now, and I don't think I saw a thread about it on here. Just trying to help out if someone encounters this problem.

 

[bitgod]

Huh, I missed it the first time then. I knew about modding the fan speed, I thought all the power mods were being done in BIOS though.

 

[krameriffic]

Huh, I missed it the first time then. I knew about modding the fan speed, I thought all the power mods were being done in BIOS though.

Same here. That's why I thought I was stuck on my OC because I was unwilling to do a BIOS flash. I'm not sure how high the voltage can be raised through the profile though.