A stable version of Cinelerra is Cinelerra CVS at http://cvs.cinelerra.org/
Cinelerra was meant to be used on a high performance multi-processor system. The creator of Cinelerra recommended Opterons because at that time they were the fastest to decode and apply special effects in real-time. These days processors have changed. The cheapest total system is still AMD even though Intel processors may seem to be cheaper. AMD systems are easier to setup in Linux. Intel system with the Core 2 Duo processors are a bit harder because you need to pass special kernel parameters at the boot loader. With the Core 2 Duo processors, do not use a kernel less than 2.6.19. Either processor will work, but I would pick AMD because they are cheaper and you can use your original DDR memory.
For any computer, I recommend buying ECC memory and a very, very good power supply. ECC memory will help minimize problems when using two processors or more. The power supply brands that I recommend are Enermax, Seasonic, and Zalman.