Thanks for the tips :
My source files are MP4 and my processor is running at 100%. I think it’s all about the project itself : a 35 minutes cut-up film with 3 layers :
layer 1 : 1 sequence per 1 second with effects,
layer 2: 1 sequence per 13 seconds streched at 33% with effects
layer 3 : 1 long sequence streched at 2 % with effetcs
I use NewblueFX for the grain and luminosity and contrast…
It’s very experimental stuff!