You are CERTAIN that your memory is installed in the SECOND and FOURTH slots over from the CPU? The A2 and B2 slots? If you install the memory in the A2 and B2 slots, which are the second and fourth slots going left to right, and you have verified memory issues, then it can only really be three things.
1. Faulty motherboard
2. Faulty memory (Or incompatible with that particular motherboard.)
3. Bent pins on the CPU (Or incorrectly installed CPU cooler CAUSING it to ACT like it has bent pins, because the CPU is cocked due to uneven pressure in the socket)
If the memory IS installed in the second and fourth slots (For 2 DIMM population) and none of those things are to blame, then it is not a memory issue almost certainly. I say almost, because electronics can be fickle so, you never know and should never say never or it will come back to bite you in the soft parts.