Thank you for posting query on forums.
Adobe Dimension CC heavily use CPU for rendering. So it is normal to see 100% CPU usage while rendering.
As additional data, we don't yet have GPU acceleration. The rendering platform and materials we're using are currently not supported on all GPU platforms so we're continuing to investigate but want to roll it out to everyone at the same time if we do it.
When you do it, roll it out to me, please.
Please vote and follow the idea on our Ideas forum as we do status update notifications there. We won't be alerting about feature updates here as these forums are difficult to track.