Yeah that does not sound like a successful Memtest run at all. Time to do a stick by stick and ram slot by ram slot memtest mate.
Do all the sticks one at a time in a single slot. Then when you know which sticks work perfectly, that one of those 100% sticks and run memtest in each ram slot on the board. It could just be you have a dodge ram slot. Often dust or some stuff gets into the slot and can cause havoc.