I was terribly mistaken. I wrongly read BIOS date, so I installed that from 2009 (it was 16/09/09 not 16/11/09). Of course BIOSes in post #1 are up to date. So stupid... So I flashed 800M/S ones just to check it. Still the bug. Than I tried the default ones and it seems not to freeze. I "boiled" water to 50 degrees -> temperatures on the PCB up to 76 degrees (power section). Any vendor info change make the VGA unusable. That's strange for me. I also have such question: in RBE in GPU registers you usually increase the highest voltages (0x18). But in these OC BIOSes there is increased the 0x17 register (from 1.0375V to 1.15V or higher)? How does it work?