I have one rig with 2 5830s and just ordered my second with 4 of them... 
The two I have were unstable anytime I tried to clock above 970, or memory below its normal 1000... what gives... how are you guys able to OC them so high and they last for days. (shrug)
The two I have were unstable anytime I tried to clock above 970, or memory below its normal 1000... what gives... how are you guys able to OC them so high and they last for days. (shrug)
Make sure when your dropping the memory, between 400-600 the card is extremely unstable. The Sapphire 5830, has a power save mode, which underclocks the card to 157/400 I think. ** I know the Core Clock speed is for sure, not the memory clock speeds in powersave mode **
Drop the memory clock all the way down to 300, make sure that the card is running above the powersave 0.9V
MSI Afterburner - Can't do it ** not that I know of anyway **
If your using ATI Tray Tools, set the Voltage profile from 0.9 to 1.163 then save the core clock somewhere between 800-1000 or where every you want, and the memory down to 300
If you bump the core above 828 I found that the card hardlocks using the 0.9V card profile.
Start by adjusting it at 5MHz increments and test for a couple minutes mining, making sure you keep your temps below 80C. You can run the Temps higher, but its not recommended for long term use, especially 24/7 100% utilization lol
When the card starts to studder back it off by 20MHz, then start playing with the AGGRESSION and WORKSIZE and other RPC Miner options.
It takes some playing around with to find the sweet spot for the card in your system, but when you find that hotspot, she's good to go for a long time
, unless some fails of course 