The problem with the pictures I’ve taken is that the effect is hard to notice, but I will post them later.
I used the same cable to test with the Framemeister. Previously I was using the old SNES PAL RGB cable that retrogamingcables provided that had not luma sync, and I had image noise also only with OSSC. I guess that the Framemeister is somewhat filtering all those image issues.
I have also a SNES RGB NTSC with csync cable from retrogamingcables that I may test in some days.