A "Reference" set means the ROMs are matched exactly to the database used by the MAME 2003-Plus developers. MAME is notoriously picky; if a ROM file is missing even one tiny data chip dump, the game won't boot. Using a reference set ensures 100% compatibility. 2. Full Set
. While this is larger than "Merged" sets, the convenience of individual file management is often worth the extra ~8% of storage.
: It requires significantly more storage space than "Split" or "Merged" sets because shared data is duplicated across multiple ZIP files.