Daz Studio become really slowly

Hi... i've been working on a scenary with a lot of props with no problem til yesterday, Now I load that scenario and try to load every figure with a merge and that merge takes about 1 hour until the figure shows in the scene ans then, it takes about 10 minutes or more betwee you do every operation, selctingm deleting, moving... is impossible to work with daz studio. why this can't be now suddenly?
I'm working on a i5 with 8gb ram, nvidia 960 4gb and windows 10 64 bits and the DS takes only 2gb ram as I can see in the process manager.

Thanks