There are no problems with latest driver.
But I just came to think of your A.I. setting in Catalyst Control Panel.
Make sure A.I. is enabled and on the standard setting, not advanced.
This is important since you have a dual core gpu.
Otherwise from that... and if your system passed all stress tests... I'm blank.
SH4 runs here rock solid and never had any glitches, so all I can say is, that it can be done. But that'll probably not cure the broken heart...
/edit: if you insist on trying older drivers, AMD do indeed have them all for you!
Click on your wanted driver and on top of the screen is a link to previous drivers.
Here's for Win7-64 bit:
http://support.amd.com/us/gpudownloa...w_vista64.aspx