If you like then do a small tweak to speed up rendering.
Go to SH3D installation folder : "C:\Program Files\Sweet Home 3D "
create a new file : "SweetHome3D.l4j.ini "
Add following lines :
-Xms320m
-Xmx768m
-Dcom.eteks.sweethome3d.j3d.PhotoRenderer.lowQuality.antiAliasing.min=0
-Dcom.eteks.sweethome3d.j3d.PhotoRenderer.lowQuality.antiAliasing.max=0
-Dcom.eteks.sweethome3d.j3d.PhotoRenderer.highQuality.antiAliasing.min=0
-Dcom.eteks.sweethome3d.j3d.PhotoRenderer.highQuality.antiAliasing.max=1

Save the file and Re-render to see the result. [:)>-]
* .ini is the extension format of the file.
-Xmx768m : is the Maximum Memory to be used that depends upon your computer RAM.
-Dcom.eteks.sweethome3d.j3d.PhotoRenderer.highQuality.antiAliasing.max=1 : is the antialiasing to be used in high quality. Default for minimum 1 and maximum 2 in high quality rendering. Higher value slow down the rendering time but gives quality.