Ipad is slow with shaders because of high resolution

I own an iPad Pro 10.5" from 2017. It’s an older device, but it’s surprisingly powerful for everyday tasks, and its 120Hz display is simply stunning.

I never jailbroke it, so I initially didn’t think running emulators was possible. However, I stumbled upon AltStore and decided to give it a shot. I installed Retroarch because its 4:3 screen ratio is perfect for emulating old consoles. I even paired a PS4 controller via Bluetooth, and it runs like a dream with the cores I’ve tested.

However, I encountered a problem when enabling shaders. Many of the more demanding shaders run poorly. I suspect it’s because of the iPad’s high resolution (2224x1668), which requires a lot of GPU power to handle these intensive shaders.

So, my question is, how can I mitigate this issue? I’ve tried changing the resolution in the retroarch.cfg file, but it doesn’t seem to affect anything, and there’s no option in the user interface to adjust the resolution.

Is there a way to run shaders at a lower resolution or any other suggestions you might have? I’d greatly appreciate any ideas.

P.S. On a side note, I had some trouble with the 120Hz screen causing jerky scrolling. However, I managed to solve it by changing the refresh rate in the iOS settings to 60Hz, and now it’s smooth sailing.

for the jerky motion, you can also try setting the vsync swap interval to 2.

For the shaders, depending on the shader, you can change the output scale factor on the last pass to something like 4x (which would probably be around 960p), but this will make CRT effects (scanlines, masks, etc.) look really terrible.

If you’re after CRT effects, your best bet is to just use lighter shaders.

Running PAL versions and running with enlarged borders can be done to squeeze out more FPS, but it’s probably best to try lightweight shaders instead of these compromises.