[Freesurfer] Data differ depending on OSX version

Dear freesurfer,

As i understand from a previous forum thread, it is recommended that all the data is run on the same computer with the same operating system.

However, what is the reason for the differing results when I am running the same 10 subjects on a MacPro and iMac respectively (please see below):

*MacPro:* build-stamp.txt: freesurfer-Darwin-lion-stable-pub-v5.3.0 13.4.0 Darwin Kernel Version 13.4.0

*iMac: * build-stamp.txt: freesurfer-Darwin-lion-stable-pub-v5.3.0 11.4.2 Darwin Kernel Version 11.4.2

All the values are different. For example, the lh_caudalmiddlefrontal_thickness is on the iMac 2.472 and on the MacPro 2.537.

Is it because of a randomization generator in FreeSurfer?

Best regards, Kasper Jessen