Out of boredom I tried all RAM slots and it runs as good as before in each configuration. Replaced 1080 with 1050 and i digged out X30 magnification to find nothing interesting in these slots.

I don't know what BIOS version was present on my first run but none of my keyboards worked so its updated to 2301. Perhaps its my luck and they botched xmass release. I'll check for newer one later. Now I wonder why shop haven't respond this year...

chew* Thanks for that info on PSU.