This program never ceases to amaze me with how many hidden actually good things it has that are really unintuitive to find unless you looks all over and at the same time the mess that it is on a fundamental level with its memory leak problems... Will we reach the day where the mythical being known as "Daz 5.0" that will fix all our troubles be out? Then again, I can imagine the release will be anything but solid if we ever find ourselves at that point.
If you wish to further improve your render times, look at this: https://www.youtube.com/watch?v=HBev_2ecxwM&list=LL&index=9
He talks about a few products you can find here as well to improve your render times like "Scene Optimizer", "Instancify" and "Ghost lights" which were added by Daz studio recently in their newest update, but I haven't tested them out and I imagine not everyone updated to the latest version.