Problems with Raspberry Pi 3B and MAME-LIBRETRO

[MartyG]

If it's running Jesse it'll be a problem - if it wasn't a 128GB download I'd take a look and see if a quick update to the /boot files would fix it.

The Pi3b+ does have a higher clock speed (1.4GHz compared to 1.2GHz) but try running it at full speed for more than a few minutes without any additional cooling and it quickly hits the thermal limits and throttles back. The Pi3b can overclock with cooling too, the FLIRC cases are excellent for this and well worth the price if you're pushing the Pi3 hard.

[Jaz]

Yep grabbed a Flirc. Great case.

[MartyG]

It looks like RetroPie was updated to Stretch on 14th April 2018, so if the images were based on RetroPie before that they were on Jesse which doesn't work with 3b+, so this is probably the reason the images are having issues booting on the 3b+.