So overall I would have 4x2GB RAM but 2 different models of 2. The Tracer (the one I want to buy) and the original BallistiX (the one I have) have the same exact cas latency, volts and timings. I was just worried if I had to have the same exact 2gb ram model
More aboutasrock m3a770de memory mixing possibility
It is best to have a matched set of ram. But if the ram is compatitable with each other then it should not be a problem. I have mixed ram and no problems.
You'll be fine with that mix, although as Al said, you should try and match if you can Moto