Hello,
You should run some matlab codes or the like (stuff that the guy said he would do like coding) on your imac and then on your macbook air and then come back to us with with results you have actually checked. As for asking me if I did a mistake.. I doubt it, I'm a PH.d in Mathematics and running basic codes won't confuse me.
1.) I don't have mathlab.
2.) I never said you made a mistake (someone else did).
I'm just saying that the CPU difference doesn't make sense for a 45x difference. I have no idea why you are seeing this difference.