When I wrote the first post I was afraid it will happen…
…actually it’s more “my pc’s better than your mac” 
Anyway, I’m happy because I got many very useful and kind answers, thank you all 
Edmond
@rumdrum: you mentionned VEPro, I use this wonderful soft but what do you mean by “VST linked”?
@papi61 : sorry, Hans Zimmer works on Mac (http://www.cinezik.org/infos/affinfo.php?titre0=20121005182011)
I don’t know about his team of 10 composers…
@jpgtr: it’s a mid 2009 MBPro 2x3.06 GHz with 8 gig of ram, 2 SSDs (I put the optical drive in an external case) actually I charge it with Spectrasonics instruments + many sound libraries in VEPro without a problem. It’s true that it’s not my DAW, just an audio-slave, but I think it is not far from the 8 core Mac Pro as for its power.