I keep having the same problem. In particular, I cannot render an image series, but it is alright, if I render each frame one at a time. But if I do image series, it renders the first image using the GPU and the CPU, but for the second and beyond, it is CPU only, becoming very slow. I then have restart DAZ (or sometimes restart the system) to be able to render with GPU again. Very annoying, and wasting lots of time. I have no idea what is causing it … but I feel that DAZ should have some feature, warning before rendering, whether this can happen or what to do about it. Perhaps the scene for which I try image series rendering is rather complex and perhaps it does not happen for simpler scenes … fine. But still, one should get some guidance on when this happens and what one can do about it.