Welcome to the forum
If I understood correctly, in the Mac you are using a virtual machine, right? Probably the cause is that the computer needs to copy all files to be burned in the virtual machine disc before to start the actual burning, and this require some time, mostly if the total amount of files to be moved into the virtual disc is huge.
This of course will not happen if you are using a physical machine, which uses directly the physical HDDs with no need to cache files into the virtual machine first.
Maybe you can reduce this caching time sharing a physical folder between the physycal machine and the virtual machine, and putting all files to be burned in the shared folder. In this way it shouldn't be necessary to cache files into the virtual disk first. This is only an hypothesis, actually I don't know if this workaround will work