AMD 5xxx series overclocking..

I 'm lucky enough to have a 5850 and I want to get near or surpass 5870 perf with it.. so say hello to overcloking.
Some weeks earlier I overclocked basically using the latest AMD GPU Clocktool for overcloking the clocks past what's allowed in Catalyst Control Center ( up to 775Mhz clock) and also using MSI AfterBurner to overvolt the GPU voltage..
Basically I overclock form 725 to 950Mhz with overvolting to 1.25V..
Now some issues to say:
-MSI would not overclock if you have enabled more than 1 GPU? (I have both Nvidia and AMD cards in Windows 7) at least not for me so disable Nvidia GPU or other GPUS in Device Manager..
You then overvolt and then can reeenable if you want..
I think you can overclock clocks in AMD GPU Clocktool with more than 1 GPU..
I now with MSI 1.40 have the option of doing all oc in it..
you search MSIAfterburner.cfg and add:
[ATIADLHAL]
EnableUnofficialOverclocking = 1
this goes past CCC (ADL limitation) clocks of 775Mhz..

Now what about permament oc or working in Linux and future MAC..
use a patched BIOS..
there are two options use oc clocks by default or override max oc clocks in CCC etc..
the safe way is the second..
CCC clocks are limited by ADL lib which in fact is supported on Linux so this second way is the best..
there is a BIOS in Internet of a 5850 modified to allow oc up to 1500 clock and 2250/2500 mem..
this BIOS doesn't change default clocks and power management (well last I'm not sure..)
search a 5850 oc article in geeks3d and from that search link to a BIOS..
it also speaks about needed tools..
that would allow getting oc in Linux to the same clocks.. using linux CCC..
But how to overvolt.. well there is a tool using ADL lib for Linux..
ATI Overclocking Utility allows to overvolt (theoretically) and also change fan speed if needed..