Force 256 px toggle on CRT's

[SilvaHaloOne]

I have a MiSTer with the most recent analog IO board connected to a CRT via S-video. I noticed when I was playing around in the Super Nintendo core that the default setting for “Force 256 px” is off and I also notice that the resolution the OSD reports when any game I have tried is loaded is always 512x224 unless I turn that setting on, then it becomes 256x224, which is what I understand the resolution of most SNES games to be.

When I change the setting back and forth, I notice that the image does shift a bit, but if there is a functional difference, I’m not capable of noticing it. Can someone explain the usage behind this toggle, the reasoning the default is “off” and why it might be beneficial to have it run at 512 instead of 256? If usage is only going to be on a CRT via S-video, which setting I should I have this set to?

Thank you for your time,
SilvaHaloOne

[TLPD-AVW]

By default the SNES core always outputs resolution with 512 pixels horizontally, doubling pixel width when games are supposed to display 256x224. This is done intentionally to prevent output dropouts on HDMI displays, perceptible to any resolution switches, as sometimes games can keep switching from 256x224 to 512x224 (e.g. when displaying textboxes in some games). For CRT users this is completely irrelevant, as those displays can switch resolutions instantly.
I personally don't understand why the function isn't reversed (i.e. Force 512px), but as far as CRT usage goes, you can leave Force 256px at Off. Keeping it on may cause distorted graphics when high resolution is actually required. The only thing to keep note is that you'd need to shrink screenshots horizontally later after you take them.

[SilvaHaloOne]

Great! Thank you. I appreciate the explanation.