Why are you using P4 render when you have firefly?  Firefly is far better if your computer can manage it.  On my other computer I always used Firefly but the one I'm using now can't handle it most of the time so I end up having to use P4 and I notice  a huge difference in the quality of many images... but for my purposes it  doesn't really make a difference as i do this for a hobby to amuse myself.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi