After much testing my team and I have our machines as follows:
1. MacPro Quad Core (2 x 3.2GHz Xeon)
2.16Gb RAM
3.After Effects CS3 with multi-processing switched on
4.Throttle installed and processes set to ‘6’ (https://aescripts.com/throttle-12/#more-179)
5.After Effects memory set to 90%
6.After Effects disk cache enabled and set to 2000Mb
Please bare in mind that the above machine is rendering to a Xan but we have found this to render the most efficiantly.
Hope this helps,
Mister G