I noticed loss in hashrate from a rig of mine after adding an extra ram stick, and the other mining rig has only one stick ram installed and it works very well at stable hashrate, my question is can two stick ram in motherboard affects performance? It's weird, if I remove the one stick and use only one ram stick it gives stable hashrate
What are you mining?
This is the first time that I have ever heard something like this. In general as long as you have enough RAM to generate the DAG, then it doesn't matter if you got 1 stick or 2 sticks or 4 sticks. Most of the hashing is done on the GPU and the GPU has its own RAM called GDDR5. Hence the system ram plays very little role here.
I am going to guess you are trying to mine something else. But even then, I don't see how more than 1 stick could slow down your mining. Only reason I can think of, and I discovered this back in the day when dual memory sticks were used to speed up systems and its because one of your memory sticks has a slower memory clock than the other. So for example, one stick runs at 1333mhz and the other at 1666mhz. If you run the 1666mhz alone, it will run at 1666mhz. But if you add the second stick, then both will run at 1333mhz. This might affect game performance, but never mining.