Ok thanks all!
I will precise that I'm speaking of offline rendering, so I'm not sure if the cpu overhead apply since there's no real time processing happening.
Great! So I'll increase the buffer size, be sure multi-core bounce is enable and see if it help.
I may use plugins that bottleneck the processing will have to check this.
And now I understand why mp3 take so long. If the lame encoder is not multi-thread enabled then my cpu is not exactly a single thread processing monster like a 4790k and look like it's the real limiting factor here.
Using an encoder that support multi-thread could really speed the mp3 export process. Is there anything I could use in Sonar instead of the Lame one that use multi-core?
That's not a real problem but that would be nice.
Thanks!