If you consider any dual channel mobo, already in use with 2 x 4GB in its slots A1 and A2(so B1 and B2 slots free.....duh).....will I be able to put in another 4GB ram in the slot B1 or B2(so now three ram sticks in A1, A2 and B1 or B2.....so in total 12GB of memory.....also all sticks with same specs and Brand)....will I face any issues ?