Never seen either used, did you mean Gigabytes?
Most programmers don't have a clue about SI vs IEC Standard Names.
The correct word for 10^9 bytes is gigabyte and for 2^30 bytes it is gibibyte. I am not very careful when I use GiB or GB. When I wrote SdFat I did the following to point out storage is decimal.
cardSize: 3965.19 MB (MB = 1,000,000 bytes)
fat16 formating type, have a limitation of storage per file which i believe is 4GB,
FAT16 volumes are limited to 65,524 clusters and on SD cards, the max cluster size is 32,768 bytes. So you can't have a file larger than 2,147,090,432 bytes on a properly formatted FAT16 SD card. SDHC cards that are larger than 2,147,090,432 bytes must be formatted FAT32.
The FAT file size limit is 4,294,967,295 bytes, one short of 4 GiB. For disks on Windows 2000 and later, FAT16 volumes can have 65,536 byte clusters so you can have a 4,294,180,864 byte file on a FAT16 Windows disk.