Thanks for the help Arch,

Just to confirm you know i have the same problem using a different motherboard - Asus P5E3 Pro Intel X48 (Socket 775) DDR3 Motherboard. Both motherboards show same freezes. I am going to put my old motherboard (Striker II) back into my pc and maybe buy some new RAM. Problem is, the list showing the RAM (for Strike II) is a few years old right? Would it be hard for me to get those RAM modules nowadays?

Probably, however, one way to overcome this can be to exactly match listed RAM's specifications with the available RAM. But keeping in mind that these are Asus boards I will keep my fingers crossed till things actually work out.