MATRIX INFINITY issues...?

Hi Fellows

I have a NTSC PS2 Console V15 Revision Board GH-052-32 modchipped Matrix Infinity 1.68 , upgraded 1.93

NTSC PSX-PS2 games = No problems

PAL PSX Games = games boot fine, sound ok , but video skip a lots (tried severals (metal gear solid) same !)
PAL PS2 Games = games boot fine, video is perfect , but i have a audio vs video 3-4 secondes delay.......like the video is 3-4 LATE again the audio that sound 3-4 in advance ... exemple TIME SPLITTERS 2

Did you know why specifically and what i can do to resolve the issues ? its really annoying

it will be EXTREMELY appreciated since i have spend the last 3 days on google and didnt find anything about theses issues on a NTSC PS2 trying to play PAL PSX & PS2 Official / genuine SONY discs

Any idea guys ?