Noob ROM question

[Jetsurgeon]

Hi, so I am new to building an arcade machine, I just bought a Rec Room Masters cabinet and a GMKtec NucBox M7 Pro Mini PC AMD Ryzen™ 9 PRO 6950H to run in it with 32GB ram and a 4 TB SSD. Looking at some of the TONS of you tube video's out there I THINK....big emphasis on THINK.....I may have a plan for populating my arcade. I guess I should note that I am really just wanting to play classic arcade type games (including some laser disc games like Dragons Lair) and maybe some vintage console games from Sega Genesis and Gamecube... So, my plan is to get Lauchbox/Big Box (paid version), and import MAME. I am looking at Myrient to download the MAME ROM Sets (before March 31), and I was looking at just downloading all the non merged ROM's in the MAME folder, as from what I have gathered that is easiest and would be all I needed to get started?  But....Looking though at Dragons Lair specifically I have read you have to have the CHD files for that, but they are only in the "Merged" folder in Myrient....so if I go "merged" I would then need the Merged ROMs, the BIOS-devices files and the CHD files? Then organize it and let Big Box sort it out? Thanks in advance...

[JoeViking245]

The CHD set only comes as a merged set.  Your non-merged MAME ROMs will work without issue with the CHD set.

In a non-merged ROM set, each game file contains all it's necessary BIOS, Device and System files to run.  e.g. Operation Wolf (opwolf.zip) will contain its game files plus the necessary files from the required Device file cchip.zip.  Note, in your non-merged set, you will still see the 2 files opwolf.zip and cchip.zip.  And realistically, you could delete cchip.zip and still be able to play opwolf.zip (and any of its clones [opwolfb, opwolfp, opwolfj etc.]). But don't do that.  

 

A note about CHD's - Some food for thought...

• The are 640 of them (including clones)
• 351 are parents
• 57 of those are considered "Working" (by MAME's standards)

(these numbers are from MAME release 0.266, but should still be close to the current 0.286)

[Jetsurgeon]

Thanks, that helps! I believe I have to get the .281 release as the non merged ROM files in Myrient are dated 28 Sep, 2025 and the .281 release was 26 Sep, 2025.  It's good to know the CHD files will work with the non merged ROMs, I really loved Dragons Lair and have been excited about finally building an arcade cabinet so hopefully that's one of the 57 working ones!!  Will Big Box be able to tell which work or don't, or is it trial and error? Or is it folly to download 640 CHD's? Some (like DLair or Cobra) are  14 GB each while some are 30 MB....not sure what the whole list is size wise....

[JoeViking245]

47 minutes ago, Jetsurgeon said:

.281 release as the non merged ROM files

Just be sure to get the matching MAME 0.281 release (the emulator to go with the ROMs).  (see more below)

49 minutes ago, Jetsurgeon said:

Will Big Box be able to tell which work or don't

LaunchBox/Big Box don't care if they work or not.   They merely passed along the command line parameters you provide (or what they auto populate when you add the emulator to LaunchBox).

To distinguish, LaunchBox is what you use to add your Platforms, emulator and games and organizing it all through platform categories and playlists.  Quite a few people actually just use it as their working frontend.  Big Box is for showing off your collection in a "pretty" fashion.  And the "intent" of both of them is to play games.  Many get caught up in building their collection and making it pretty and forgetting to actually play the games.

When you're ready to import you Arcade games, you can use the MAME Arcade Full Set Import Wizard (via Tools - Import). As you navigate through the wizard, your given many options.  e.g.

• point to the folder containing your ROMs
• Select the version (0.281 in your case)
• On the Would you like to automatically install and configure MAME? screen
  • Select the 1st ("Recommended") option  (this is what I was talking earlier when I said "see more below")
  • LaunchBox will download and install MAME 0.281 for you as the emulator for your Arcade platform
• One screen down the road will ask about "filters" with several checkboxes
  • One of the boxes is Skip games unplayable in MAME.  
  • LEAVE that one checked.
    • This I suppose is how BB "will be able to tell which work or don't"  
  • Actually, probably them all alone (use the defaults)
• The defaults on all the screens are that way for a reason.  They just work.

 

1 hour ago, Jetsurgeon said:

Or is it folly to download 640 CHD's? Some (like DLair or Cobra)

Make use of resources available to you.  e.g. The Arcade Database Search for a game and see what it says about it.

Search "dlair" and you'll see a pretty green dot indicating it's playable.

Do the same for "cobra" and you see this:

 

RE: ROM files and their location,

• put the ROMs where you want the before importing
  • This is a personal preference and will be dictated by your personal degree/level of OCD.
  • /LaunchBox/Games/Arcade/  is the default location. But by no means is required.
• CHD's ROMs come in individual folders, per game
• The easiest way to use those is to place their folders in the same folder as your MAME ROMs
  • /LaunchBox/Games/Arcade/dlair/dlair.chd
• If this is detrimental to your OCD-ness, you can place them elsewhere in their own location/folder
  • Then either in the MAME UI or by editing mame.ini, tell MAME where the ROMs and CHDs are located
  • Some modifications to the default command-line parameters will be in order as well
• Never, never, never unzip you ROMs files. Leave them as is.
  • I mean, you can unzip them to see what 's inside if you want. But MAME needs them in zip form

[xokia]

9 hours ago, JoeViking245 said:

Just be sure to get the matching MAME 0.281 release (the emulator to go with the ROMs).  (see more below)

LaunchBox/Big Box don't care if they work or not.   They merely passed along the command line parameters you provide (or what they auto populate when you add the emulator to LaunchBox).

 

Do you know how many working ROMs are available in the latest MAME release including CHD? Trying to decide if I should upgrade.

[zugswang]

7 hours ago, xokia said:

Do you know how many working ROMs are available in the latest MAME release including CHD? Trying to decide if I should upgrade.

Here is a list of all working games as of last version (see attached)

It's includes working parents + working clones.

Total working parents is 5,459. including working clones 13,617 (MAME 0.286)

 

MAME - All Working Games + Clones (0.286).txt

Edited 8 hours ago by zugswang

[Jetsurgeon]

7 hours ago, zugswang said:

Here is a list of all working games as of last version (see attached)

It's includes working parents + working clones.

Total working parents is 5,459. including working clones 13,617 (MAME 0.286)

 

MAME - All Working Games + Clones (0.286).txt 603.14 kB · 0 downloads

Thanks, VERY helpful to have the names with the ROM file names! I took that list and made the list of ROM's I need for those games (attached)....I took a thread I found with "top 100 Arcade Games up to 1986" to make the list but very helpful to be able to search the text file!! I've got my work cut out for me in Myrient...

mame list.xlsx