So I tested all the RAM sticks so far in slot A2 which is second from the processor, but the recommended DIMM for 1 stick by the user manual. I wrote a number on the original 4 sicks of ram 1,4 no errors 2,3 errors.
The RAM I tried was Corsair Vengence 2x8GB 1866mhz in slot A2 B2 as said in the...