check to see if your card has hynix memory on it
if it does get ahold of the manufacturer and tell them u need the newest bios
they will prolly ask for your part number and serial number
so if you have hynix memory this will fix your card because i went thru the same thing
i found the correct bios for my sapphire hd 5670 and reflashed the card and have had 0 problems since
where before it was crashing ever 10-30 min
also im running catalyst 10.3b
i did everything u listed shuttle
and nothing it still happend
and within 10 min of me playing wow
i have an athalon 2 620 quad core
4 gigs ocz ram
asus m4a785-m
sapphire radeon 5670 1 gig
win 7 ultimate 64 bit