640x480 shimmer/vibration

[Birfield]

So I have a shimmer/vibration when I use 640x480 resolution both in interlaced and progressive mode that I haven't been able to figure out. For reference here's my setup:
Radeon 7850 video card >> DVI to VGA adapter out of the VGA capable DVI port >> Retrotek VGA to component converter >> Component input on a JVC AV-32320 consumer television. In VMM I used the arcade 15.7 kHz for the EDID emulation.

I don't have the computer with GroovyMAME, crt_emudriver, etc. in front of me to list all of the resolutions I've tried, but pretty much everything below 640x480 seems to work fine and all of the super resolutions I've tried seem to work without the shimmer. I suspect it's something related to the vertical resolution/refresh rate since it seems to be a vertical vibration. I've tried making custom resolutions using VMM at different refresh rates (55-65Hz) and I've tried changing different pretty much every parameter in ArcadeOSD to see if I could resolve this and have had no luck.

One question I have is ArcadeOSD has a testvfreq option which when I turn on will either have bars scrolling vertically, a grid scrolling at an angle or in some cases a mix where it switches between vertical bars or a grid. Is this something I can use to help fix my issue?

Any chance anyone here has any guidance as to what's causing my problem? In searching around I found 1-2 other posts where it seems like it was the same issue, but there was no resolution. The good news is that most of the games I want to play are at a lower resolution, it just makes the font end I want to use and working in Windows annoying.