I have a mining rig with 6GPU, each one has 3GB ram. Is it necessary the DAG file to be downloaded in all GPU rams or it is downloaded in one GPU. Furthermore, is the required ram for mining (to support DAG file) calculated for each GPU separately (3GBx1GPU=3GB) or for the rig setup (3GBx6GPU=18GB). If i install a new GPU with 8GB ram ((3GBx5GPU)+(8GBx1GPU)=23GB), will this solve the problem of ram shortage required for DAG file???