No way of telling, they might or might not, depending on the DRAM it could be a definite No, same with the mobo/CPU, if older and the DRAM is using the newer 4Gb memory ICs then irt won't work. You could even have an exact matching set of DRAM and they still might not want to play together, if you tell us mobo, CPU and the model #s of the DRAM can make a better guess or a definite no anyway