You're probably overtaxing your graphics card and it's falling back on the CPU. You can change that in your render settings. But the root problem is with your scene. You've got to look at how big and complex your scene is and take out unnecessary things. When I first started with Daz I didn't realize that objects which are not in the render screen but still present in the screen will go towards your VRAM limit. If you hide everything that's in the scene but not in the viewport you'll alleviate a lot of the burden on your GPU. If that still doesn't work, you'll need to find a way to optimize the scene for rendering. There are a number of ways to do that, depending on your scene, but one tool that can help is Scene Optimizer:
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Otherwise, if you use Google to search something like, "reduce VRAM in Daz" you should find a lot of helpful threads.
Be sure to check your log under troubleshooting. That will confirm whether you're falling back on your CPU.
