It would be very nice if you indicate how much time it took to render these images with your settings, and even better, with default Sweet Home 3D settings.

In the previous post, I added in blue my settings and the rendering times. I use a computer with only 2 cores.

Common default settings for quality 4 :
causticsPhotons=0, shininessShader=default, normalLens.focusDistance=250, normalLens.radius=1
filter=blackman-harris, samplerAlgorithm=bucket

Photo made in 512x288 pixels.

SweetHome3DExample4

rendering time : 6min 59.77s (aAmin 1, aAmax 2, gI default, dB 1)
SweetHome3DExample4

rendering time : 2h 53min 44.64s (aAmin 1, aAmax 2, gI path, dB 2)

By reducing antialiasing values, rendering time is shorter.

SweetHome3DExample5

rendering time : 8min 8.78s (aAmin 1, aAmax 2, gI default, dB 1)
SweetHome3DExample5

rendering time : 43min 14.76s (aAmin 0, aAmax 1, gI path, dB 2)

SweetHome3DExample5

rendering time : 7min 14.52s (aAmin 1, aAmax 2, gI default, dB 1)
SweetHome3DExample5

rendering time : 15min 34.32s (aAmin 0, aAmax 1, gI path, dB 2)