i dont know how it happen but yesterday at night i got a bsod in the middle of working with word document, without any heavy load on system. than i got reboot loops before posting. i turned off the psu and turned it on again. after the screen turn on, i got a strange message: recovering bios and something else. this message disapeared in few seconds . then reboot again. after all this process i finally could enter bios and this time multiplier wasn't stuck at x6 like before. it was 8.5 like it should be. i loaded optimized defaults, disabled TM and loaded windows. the ram speed was like it was in my previous board. no problems at all. now after i reformatted the PC every thing works fine and the temps under 40.
i dont know how it turned like that and what was the problem but i hope this will not return again.