A full non-merged MAME 0.260 set (around 8,000+ working games) can be ~300-400 GB , compared to ~180 GB for a split set and ~120 GB for a merged set.
In the arcade era, game manufacturers frequently released multiple versions of the same game. They created regional variants (US, Japan, Europe), fixed bugs, or revised the software. In MAME terminology:
No. Because a non-merged set includes the necessary BIOS data within the game's archive, you do not need a separate folder for BIOS files, and you can delete it if you have one. The required code is already in the ZIP.
You can delete games you don't like without worrying about "breaking" other games that might have relied on them.
At its core, a is a collection of ROMs where every single game—including its clones, bootlegs, and regional variants—is stored in a completely independent ZIP file. non merged mame rom set
The Non-Merged MAME ROM set prioritizes user convenience and independence over storage efficiency. Its self-contained nature makes it the most beginner-friendly format and the best choice for small, curated game lists. However, for large-scale archiving or bandwidth-sensitive updates, the redundancy becomes prohibitive. Understanding the trade-offs between Non-Merged, Split, and Merged sets allows emulation enthusiasts to select the optimal format based on their storage capacity, technical comfort, and usage patterns. As storage costs continue to decline, the Non-Merged format may see increased adoption among casual users, but professional or full-set collectors will likely continue preferring Split or Merged structures.
In ClrMamePro, set your scan type to "Non-Merged."
The independent nature of a non-merged set is the key to understanding its strengths and weaknesses.
Frontends work best when they can easily identify a ROM and its corresponding media (marquee, video, snapshot). With a non-merged set, you can easily filter by region (e.g., keep only US ROMs) without breaking the emulator's ability to run those games. 3. Ease of Portability A full non-merged MAME 0
With hard drive prices plummeting (a 4TB drive costs ~$80-100 as of 2025), the storage argument for Split sets weakens every year. Meanwhile, the convenience argument for Non-Merged strengthens.
Emulation frontends like LaunchBox, RetroPie, and Hyperspin interact seamlessly with non-merged sets. Because every zip file is complete, scraping artwork, video previews, and metadata is straightforward, resulting in fewer broken links and missing assets. The Downside: Storage Space
: A split set stores the parent's full data in its own ZIP file, while each clone's ZIP file contains only the files that are different from the parent. This saves storage space, but clones are completely dependent on having the parent file present to run. This setup was standard for many years and remains common .
In the arcade world, games are often built upon hardware that requires shared files (BIOS files) or parent-child relationships (e.g., Street Fighter II is the parent, and Street Fighter II Champion Edition is the child). In MAME terminology:
No
If you decide to download or build a non-merged set, keep these management tips in mind:
You can delete the parent ROM ( pacman.zip ) and the clone ( pacmanus.zip ) will still work perfectly.
Because every ROM is independent, you can delete any game you don’t want without breaking other games.