That is not true, you will just spend more time rendering. Are you using Firefly or Superfly when you render? I can suggest some settings to try.

No more time as in a render can be 10 minutes or 60 minutes.

Render quality is determined by how much processing time vs. power is applied to the image.  That power comes in many forms.  A powerful graphics card with CUDA can speed up a render a lot.  More cores/threads a CPU has can speed up a render.  If nothing else more time will result in a better render.