"you could put the render settings to maximum and it would still render, ok it would take a long time but still it would do it." The maximum render settings in P6 are different from the ones in P5. For example, dragging the quality slider to the right end in P6 would give you a shading rate of 0.1 and 6 pixel samples, where the P5 production default is 3 pixel samples and a shading rate of 0.5.