the radeon non pro version runs at 250/200 and is locked in the bios.the pro card is 275/275 and is not locked.
if you have pro card powerstrip will be the best bet.if its the non pro.dont bother trying to flash it as it wont work.
i know this because i have done so.i extracted my own bios with flashrom and with atiflash and then adjusted the clocks with radedit and flashed it back.this went ok untill back in windows when the drivers did not load.the card clocks were overclocked ok but the fact that you have no driver its not much use.
i tried all different flavors of built by and made by drivers and bios and same results every time.even underclocking the drivers wont load.
powerstrip works for the non pro to a point but it doesnt really overclock it.you need to put the line unlockclocks=1 in the ps ini file but what happens is the clocks reset back again and then speed up again every few mins(not good)
what does work,and this will only be for a while as im sure ati has heard about it and will fix it in there next driver release,is RIVATUNER(nvidia overclocking app)
for this to work you need to select customize/overclocking/more and set the clock frequency generation accuracy to high.
rivatuner click here
and if you want to try the bios yourself heres a list click here
but it wont load the drivers,i have tried them all.
ps if you try this save your original bios first and then you can flash it back again and the driver will load ok.
9make two copies to be safe)
flashrom -s 0 originalbios.rom
atiflash -s 0 originalbios.rom (original=whatever you want to call it)