All the builds are the same version. My main comp is using 100% load on all 8 cores. The render is slower while using the server. If i check the CPU Affinity on the rendercow installed on the server it reads 48, which is the correct number of cores.

@bruno, so the tilesize is the amount of "pixels" that get sent to the nodes and then the nodes themself split them into parts that get distributed among the cores?