In a split set, the parent game ZIP is complete, containing all its data. A clone ZIP, however, only contains the ROM files that have changed or are different from its parent. This saves significant storage space but introduces a dependency: the clone cannot run unless its parent ZIP is also present in the same directory.
In MAME, many games are "clones" (variants) of a "parent" (the main version). Usually, clones rely on the parent ROMs to function. non merged mame rom set
ROM managers like CLRMAMEPro or RomVault can easily audit a Non-Merged set because each game is independent. There is no need to maintain complex parent-clone dependency trees. In a split set, the parent game ZIP
This is the most cited drawback. In a full MAME set (e.g., 40,000+ machines), Non-Merged sets can consume more disk space than Split sets, and 4x to 6x more than Merged sets. For example, common sound program ROMs or MCU dumps may be repeated hundreds of times across clones. In MAME, many games are "clones" (variants) of