Performance and Overclocking

[Eilermoon]

Not exactly a specific issue, but I wanted to pick y'alls brains about performance of this build. Because the market is what it is, I've only got a few Pi Zero W's which seem to struggle running even some gba games.

A good example is Mario Kart (gba) or Harry Potter and the Chamber of Secrets (gba). My Pi doesn't run these well at all. lagging and the audio skipping constantly. I just overclocked a bit in the config.txt file with the settings below:

#arm_freq=1095 for my other unit with heatsink
gpu_freq=530
#gpu_freq=550 for the unit with a heatsink.
over_voltage=2
core_freq=515
sdram_freq=533
over_voltage_sdram=1

Which maybe helped with lagging slightly less, but still borderline unplayable.

Does this sound like underperformance or about right for the ability of the Zero W? Any ideas to improve?

I'm adding passive heatsinks so I can kick these settings up slightly, but I imagine there's more that I can be doing.