8480000000 / 1024 / 1024 /1024 = 7.8976… GB
edit: So, the insight is, anyone authoring an OS that doesn’t use power-of-2 units on machines that operate by power-of-2 is a fool.
so the OS is responsible for the file size discrepancy.
But will this mean that an 8gb dvd dl will appear to be 8.5gb on my os then? Or am I pretty much stuck unless I copy the files to my external hard drive then burn it at a friends house?