@ssssq
when I was on HDMI it was running p e r f e c t.
after perfect crt setup
First: It would save time if you had said this information from the beginning, please specify as much information as possible so that someone can help you correctly.
So the problem is probably the fact that you configure it in CRT, possibly you need to change the Dreamcast videomode, and once again I would point out that Dreamcast/N64/PSP are emulators that have these emulation difficulties.
Let's go to some questions:
Do you have your BIOS perfectly recognized in the built-in BIOS checker (green thumbs)?
Have you already tested it with the two emulators:
Flycast and
Reicast?
You can test the same game with an iso redump as mentioned in the documentation?
In addition, there is the question of the videomode I mentioned, the information appears in the recalbox.conf file:
## Dreamcast emulator
## Like N64, such a CPU intensive emulator needs a small resolution
## Consider DMT 4 HDMI (640*480) or DMT 9 HDMI (800*600). If you have a black screen on dreamcast, try DMT 9 HDMI here
;dreamcast.videomode=DMT 4 HDMI
The official Flycast documentation specifies some resolutions:
https://docs.libretro.com/library/flycast/#core-options
Reicast's official documentation specifies some possible video configurations:
https://reicast.com/guide/
Maybe this will help:
https://forum.recalbox.com/topic/23950/7-2-mode-non-optimum/10