I’m not sure what you’re getting at, maybe I can test a specific game for you?
Not just color borders on the top and bottom, but on the left and right sides as well.
Some people seriously hate them, and use custom settings on the framemeister to get rid of them.
But my old CRT TV had almost 0 overscan and always had side borders. So I like them. I just want to make sure OSSC has them by default. Here is a youtube video that shows the side borders.
I’ve not tested that bright flash specifically but you can cure that problem on the XRGB3 by using a clean sync (CSYNC) cable. The OSSC is not affected by that issue at all.
Hmm… supposedly my cable uses CSYNC… oh well.