We are using our server with different purpose and have to move from windows to linux to avoid paying for windows on many servers. However I have downloaded Catalyst 11.5 (http://www2.ati.com/drivers/linux/ati-driver-installer-11-5-x86.x86_64.run) and the Windows one is different than the Linux one and I did not see 'Power Control Settings' -20% to +20% under Linux. For our purpose it really increases performance because setting to +20% can achieve approximately 2200 million SHA1 hashes per sec instead of 1700 million per sec with a single 6970 on 950Mhz.