Subdivision surface not working properly I don't know if this is a bug or something else but when I use Subdivision surface my "View" tab is controlling both "View" and "Render". It's like I don't need "Render" option. By setting "Render" value to 4 and my "View" value is 1-2 on rendered model it will show me the value of "View" and not my "Render" value. If I change "View" value on 4 and "Render" value on "what ever number" it will show me the value of "View". I didn't try other modifiers. Is this something that is fixable or do I have to change my "View" to render stuff on the value I want?
in the Subdivision Surface modifier, the Render value is for the definitive render, the one you get when you press the Render button in the Properties panel > Render > Render, it is not for the Rendered display option you have on the dropdown menu of the horizontal menu bar of the 3D View, this one takes the View value into account. It's a bit confusing, yes.

Also, in Properties panel > Render > Sampling > Samples, you choose the final Render sampling value and the 3D view Preview sampling value. You generally don't work your 3D view with a value as high as the Render value because it would take too much time. But in Blender 2.8 you'll have Eevee which is quite fast.