Zeus, like a lot of text editors is an in memory editor, which basically means it loads the whole file into memory.

So it too is limited by the total memory available to the application.

For a 32 bit Windows application the available memory comes in at around 2 Gigs and for a 64 bit Windows application that explodes to 8 Terra bytes.

So even if Atom was 32 bit it should have 2 Gigs of memory to play with.

I'm not sure why Atom does limit files to 2 megs, but if it is because of the expansion of memory then there must be some serious expanding happening there.