PS2 has twitchy/jumpy RGB?

Hi guys, new here.
Good to find a forum with so much technical insight.

I have been so tired of modern gaming lately that I have started playing old classics again and old games I might have missed. Mostly SNES, Megadrive and PS1 games.

I was very surprised when I hooked up my PS2 again. It's a slim version 7000 series. I haven't played it in RGB in a long time.
All contrast heavy areas have this high speed twitching or shaking going on. It's especially bad on white lines and white text against dark backgrounds.
The PS1 in comparison is rock solid on the display (a Philips CM8833 monitor) no twitching or shaking at all.
Is the PS2 RGB output just bad? I'm really surprised I don't remember this from gaming on it back in the day.

 

PS2 RGB has sync-on-green and your display probably isn't coping with it well. To fix you'll have to rework the output circuit if it's possible at all with your revision...

 

SoG is output only if the component video ouptput is set as RGB and a progressive mode (480P or higher) is active.

OP: Make sure the component output is set to RGB and no matter what do not enable progressive mode within the games because you will lose video completely as the PS2 cuts output on CVBS and Y pins when generating HDTV signals. (Playstation consoles have no dedicated Sync pin so the composite video pins are used as sync signal source)

 

There's a device called MG 3000 or something, that somehow outputs HDMI directly out of the AV Multi Port. Something like the WiiHDMI dongle.

Here's some info: http://psx-scene.com/forums/f291/hdmikey-playstation-2-possible-lets-find-out-109365/

Probably doesn't do anything with the image quality other than just directly output HDMI instead of using Component Cables and a HDMI Converter.

 

Thanks for the suggestions.
To clarify a bit I am using a Scart RGB cable into a Philips CM8833 monitor which has Scart input. It has a manual RGB mode button so it's easy to see that it's locking on to the RGB and not the composite signal.
I tested some different PS1 games to see if it's just some games that have this but they all do.
For example
Parasite Eve on PS2 slim = Twitchy lines
Parasite Eve on PS3 60GB BC = Twitchy lines
Parasite Eve on PS1 = stable lines

I don't get it, is there something different in the output chip on the PS2 and PS3 that causes this perhaps? I tested on one other display as well, a LG flatron tube and the result was the same. This is only for Scart RGB mind you, Component is fine.