>>TpwUK-Also take into account that rendering engines are starting to licence by the core - 8 cores = potentially 8 licences.<<

This is applied for 3Delight..Maxwell-VRay-Fryrender offer a single license with more nodes,this means that you buy a license then calculate your render scene with your main computer+others you have
no problems how many cores you have

All we know (mac &pc users) best and wrong things of both OS,don't want to talk about that,just talking about render and this only means power to CPU

this is a benchmark where you can see what i mean


http://randomcontrol.com/index.php?option=com_rcbench&Itemid=140&benchid=1