@RedLion: Doesn't make a bit of difference that his "video card is weak". This is pSX, not ePSXe. In any event, this has nothing to do with his graphics.
@Mother Eater: This is a known problem that has yet to be fully addressed. There is no way currently to solve this problem, besides what you've already tried. I hate to say it, but you'll have to wait for a future release to solve this problem... :/