Black frame insertion flickering at 320x240 120Hz. Bug?

[Nikorasu081]

I'm gaming on a VGA CRT monitor via HDMI to VGA. I created that resolution in the config.txt with hdmi_cvt=320 240 120 I'm having some issues though.

1. For some reason refresh rate shows up as 117Hz instead of 120Hz.
2. Black frame insertion causes flickering in certain emulators, such as Gamebatte, mGBA, BettlePCE, Mame 2003, FB Alpha.
3. Picodrive is both a Genesis, Sega CD, and Master system emulator, but for some reason I get more flickering when playing SegaCD and Master system games.
4. I get flickering on games that are the same resolution. I tested all Sonic games on Genesis none of them flickered. I then tested Sonic CD on SegaCD and I get flickering. Castle of Illusion on Genesis I don't get flickering. But I get flickering on Mickey Mania, both games same have the same internal resolution.

Snes9x-2010, FCEUmm, all work fine with no flickering when using black frame insertion. What's going on here? Why do I get flickering in some games/emulators but not others? What Is causing this issue? Is it a BUG? I'm not using any shaders. I'm using all default settings in retroarch. Only thing that is enabled is black frame insertion and integer scaling.

[dankcushions]

@Nikorasu081 i suspect it’s just the system bandwidth not keeping up with the demand of 120hz. eg, with shaders on i’ve noticed mega drive emulation can drop frames in some games but not others. i guess mega drive emulation does a lot of memory transfers or something else that causes the gpu to fight for bandwidth.

[Nikorasu081]

@dankcushions I'm not using any shaders on any of the emulators. And what about the 117Hz instead of 120Hz, what's the deal with that?