What are the most common problems with using a CRT with the Raspberry Pi 4?

[SolidShook]

When compared to the 3b? I think it might be worth gathering all the issues in a single thread

I know the biggest one is that the Pi 4 has to underclock itself to run AV out, but I've found that it's still powerful enough to run games fairly well. I've been emulating SNES and Genesis games with runahead frames and it all seems fine.

I've heard that a common problem compared to the 3b is something to do with aspect ratios, but I've not quite experienced that myself yet.

Does anyone know of any other problems or frustrations, or features that were present in the 3b but not 4? I have ran into them in other threads.

[dankcushions]

@solidshook not an expert, my understanding is that tvservice is used heavily in CRT guides/scripts, and this is only partially functional on pi4, since it is a call to the fkms firmware layer that is being depreciated.

raspberry pi are instead moving to the open source driver stack, which aims to be a more standard KMS offering, where the way to use custom modes is via DRM modesetting or xandr, the latter of which relies on X which retropie doesn't use by default, and i believe the former might not have enough flexibility.

still, an approach should be possible, with some work.