I am that lucky guy who got this mod on my Gigabyte HD 3850 512mb card.
Right now 860mhz on core is max what i get out with this "locked" bios. Without that mod and 1,256 v i got only 805 mhz max stable under benching. Memory is Hynix 1.4ns and right now i could get stable bench clocks with RTuner 1044mhz with stock vmem.

3DMark06 skore is 13568

http://service.futuremark.com/compare?3dm06=5461767
Not bad
Now in need of a good bios mod. So can go for 1000mhz.
And about temps. I have default Zalman cu700, bench temps i saw in load with RT monitoring were 81C. But those were with very high vcore, wich i just put on, knowing that those will be enough to pass with 860 core speed. Now try to lower them to optimize.

Thanks Jaan!