For the memory best use either BIOS default setting, or load an XMP Profile in the BIOS. And like Nikorr mentioned, it could be anything incl PSU. If you have another decent PSU or if you can borrow one, it is worth trying.
Just giving an update....
Since setting BIOS to XPM haven't had a freeze up in 2 days. Will continue to monitor a couple more days til I consider this one solved.