Nobody can tell you anything without proper system info or other technical details like exact comp settings, layer settings and so on. And well, Mac + Raytrace 3D? I hope you are aware that this is possibly the worst imaginable combination for this stuff...
Thanks for the reply. So the raytrace settings in AE are unreliable? I'll get my AE guys involved on here and they can provide more light. I was just hoping someone could tell me whether the raytrace settings only work on the full version of AE and not on the render only version.
Systems are a mix of older MacPro towers with minimum 16gb RAM and OS 10.7-10.9 and some MacMini's with 16GB RAM and 10.9
For Ray-traced rendering to be supported by the GPU you have to have a compatible NVIDIA card installed and configured. Otherwise the CPU will render the effect and it will take forever. This has nothing do to with Mac vs Windows and everything to do with machine configuration. If you are using the Adobe Media Encoder then any Ray-traced rendering will only use the CPU and be extremely slow. Getting different results from different machines means that you have configuration problems with some or all of the machines. Before that can be diagnosed you need to look carefully at the settings in detail and examine the workflow. If you want us to come up with ideas then we need those details.