I want to take the system drive from a Mac Pro (running El Capitain) that died, and put it in a similarly equipped HP xw8400 workstation. (Dual 2-Core Xeon CPU, 8 GB RAM Nvidia Quadro 4000 GPU, Smasung 256 GB SSD System drive.) Years ago I took a Leopard hard drive out of the last generation G5 tower, put it in a Dell mini tower, and with a CD that emulated EFI, (Boot 1 2 3) it booted. It worked great for years, until I got this better equipped Mac Pro with El Captain. Does anyone know of a current EFI emulator CD or USB image that would make the HP run El Captain? Thank you!