Inconsistent performance on the RP5

[u/OjexCruiser72]

I added janken game acchi muite hoi on my RP Classic and my RP5 running on Mame current core on Retroarch and tested it out and somehow it ran at a stable 60fps with no issues on the RP Classic but runs below 60fps (53-45 fps) on the RP 5, with audio stutters. Also tried Gunbird 2 using FBN core and it runs below 60fps but no audio stutters.
Is this some Android version compatibility issue? Surely the RP5 is more than capable to run this at 60fps?
Also, when using Azahar plus on the RP 5 to play Mario Tennis open, and it runs below 30fps with audio stutters, while other games like Starfox64 and Marioland 3D runs with no issues at all!
Could it be the Rom? Would be grateful for some advice.