In your DAZ Studio Render settings under Advanced, you will find the area that shows your CPU and graphics cards.
Below the "Photoreal" but above the "Interactive" areas, you will find a box labeled "OptiX Render Acceleration."
In my testing, checking the box to turn this on speeds up my renders, sometimes knocking off a third the render time, sometimes even half!
Others in the benchmark thread on the forum have gotten different results, some saying this even slowed things down. I'm interested in people's results.