@martina.menegon your issue sounds like the fact that retina displays require rendering 4x the amount of pixels in the patcher. As mentioned in previous threads and in the advanced scheduler settings vignette of the max documentation, you may wish to "Open in Low Resolution" to reclaim your expected performance.
On a Retina Macbook, if you have a patch that is performing a lot of user interface drawing, such as rapid updates to JSUI, you are possibly backlogging the queue, which can have an effect on scheduler performance. On these machines, GUI rendering costs are roughly 4x expensive, unless you disable high resolution support (patchers will look worse). To turn off high resolution support for Max, go to the Finder, and Get-Info (cmd+i) on the Max application icon and check the "Open in Low Resolution" box.