Hello. I was using two sticks (2 X 1GB) of TWIN2X2048-6400C4 on a Gigabyte MA770-UD3 without issues at 4-4-4-12 @ 2.1V.
I recently installed another 2 X 1GB of the same stuff but the system is unstable. Getting errors with prime 95 and memtest . The latter pair alone are fine. The problem is only with all four dimms populated at once. I have manually set the timings to 4-4-4-12 @2.1V.
AMD Phenom II X4 955 BlackEdition
MA770-UD3
620HX PSU
1 TB WD HD
Any suggestions welcome.