Before we go further, a critical distinction: A MAME ROM is not a "game file." It is a dump of the actual, physical ROM (Read-Only Memory) chips found on arcade PCBs (Printed Circuit Boards).
Because arcade games shared hardware (e.g., Capcom's CPS-1 or Neo-Geo), ROMs are highly interdependent. A "ROM set" requires:
Crucially, MAME ROMs are version-locked. A ROM that works perfectly with MAME 0.72 may fail to load in MAME 0.250, and vice versa. This is because every time MAME improves its emulation of the protection chips or video hardware, the required CRC (Cyclic Redundancy Check) hashes of the ROM files change. mame 0.72 roms
Neo-Geo emulation peaked with 0.72. Unlike later versions that require a specific Neo-Geo BIOS (neogeo.zip) with strict security checks, 0.72 was relatively forgiving. KOF 2002 remains a community favorite for its balance.
Around version 0.73 and 0.74, the MAME dev team made a controversial decision to rewrite the CPU core system to be more accurate. While this was great for preserving history, it absolutely slaughtered performance. Games that ran perfectly at 60 frames per second on a Pentium III in MAME 0.72 became slideshows in version 0.75. Before we go further, a critical distinction: A
Consequently, 0.72 became the "Goldilocks Zone"—accurate enough to play thousands of games correctly, but fast enough to run on the hardware of the time (and even on modern low-power devices like the Pi Zero).
Because MAME 0.72 is old, it is often easier to find a "Full Set" than individual ROMs. Crucially, MAME ROMs are version-locked
"Non-Merged" vs. "Split" Sets: