So I've been working on these for quite some time... Lots of up ands downs in trying to get these to work.... Especially with Apple knocking off the ability to run more than 2 external Nvidia GPU's in 10.10. Over at CreativeCOW people with Cubix & Netstor expansion chassis are limited to 2 Nvidia in total and only with running an ATI as your display. I initially was going to use a Splitter for the box so you could connect 1 pcie slot feed the 3, but here was when the problems came... I could only get 3 cards total recognised but they all had to have a MAC EFI.. Otherwise only 1 internal GPU and one External was showing up... and that was coinciding with the reports at CreativeCOW. The reason i created these was the fact i was in desperate need for render power and a neat solution.. I hate cables and mess all over the desk.. and i don't have the money to spend on a Nestor and Cubix etc.. I don't consider these replacement to such units but as gpGPU is progressing and i hate PC's i think this is a viable solution for anyone. If anyone is interested in them let me know... ....................... They allow for 3 external cards and a standard ATX psu. You can run 1, 2 or cards simultaneously. 2 Standard 120mm Fans for airflow. They are RenderBoxes not expansion chassis you will require an available pcie slot for every card you want to run externally. Tell me what you guys think????