actually, one of my DMGs turned out to be one of the crappy-sounding CPUs. i remember trying LSDJ 4.7.0 on it for use in a live performance a month ago, but sadly the CPU still mangled up the drum kits.
hopefully this shred of anecdotal data is helpful at all. but it would be really helpful to have some kind of thorough collection of comparison recordings across as many CPU types as possible - having proper reference test recordings might help to identify what kind of CPU a DMG has, without having to open it up.
Are you trying to avoid pulling the battery cover off? The hole in the case that the tab locks into is a window to seeing what cpu board your DMG has. No need to open the entire thing up, takes 2 seconds, much faster than trying to record and compare waveforms to figure out what you have.
Or did I misread something?