Hi,
Took me a while to figure out what was going on, but it appears when I run MAME and I have an external monitor connected (In fact I have 2 external monitors. I usually have my laptop closed and used the dual monitor setup. However, even with 1 external monitor connected I get the same issue) then MAME runs at under 50% and the games are just slow and choppy. No idea why this would happen. I've changed the resolution on the external monitor to be low, but same issue. It's been a while since I had MAME up and running and don't recall having this issue in the past.
I'm running the latest version, 0.243, on an M1 Mac. The Mac has 32GB memory and 24 cores, so it's got plenty of power.
The two monitors are Dell P2415Q monitors that have a maximum resolution of 3840x2160. But they are both running at 2560 x 1440 @ 30Hz.
Maybe this is a known issue and maybe there's a solution for this too. I hate to be restricted to only use MAME on my laptop screen and not my actual monitor.
The other thing I can state is that one monitor is connected via USB-C into a USB-C Hub. The other monitor is connect via HDMI directly to the laptop.
I am totally at a loss as to how to even go about troubleshooting this, or resolving the issue, so any help would be much appreciated. I'm sure I can't be the only person using external monitors and running MAME without issue.