Catalyst 11.6 in Linux allows you to bypass the BIOS limits now. 11.5 didn't.
Adapter 0 - ATI Radeon HD 5800 Series
Core (MHz) Memory (MHz)
Current Clocks : 975 300
Current Peak : 975 300
Configurable Peak Range : [600-875] [900-1200]
GPU load : 99%
I've tested it on both Sapphire and Gigabyte 5830 cards.
Cheers,
Kermee
Interestingly, glakkeclock (which is an excellent program BTW) can't overclock my 5830, which aticonfig can.
I ran into this with my throttling script where I use glakkeclock to read the card temperature and adjust the core clock to keep the temp at a preset limit. On my 5830, glakkeclock can't get the gpu above 900 MHz but when I substitute aticonfig I can go as high as I like.
I need the auto-throttling because I keep my miner in the garage and it goes above 40C in there in the summer. I reckon it's better to lose a little performance than pay to air condition my 80C cards.