I'm not sure it's such slow, I finished the first level of wonderboy on SSF. I notice that a CD won't run on a real saturn if there is no audio track on. Is there another mandatory thing to do to a prog works. Mine only displays text, the frameskip and the game name but not the game display (NBG1). Also I fill the palette only before putting the picture in memory.
I use that code to init display :
slInitSystem(TV_320x240, NULL, 2);
slScrPosNbg0(toFIXED(0.0), toFIXED(0.0));
slScrPosNbg1(toFIXED(0.0), toFIXED(0.0));
slScrAutoDisp(NBG0ON|NBG1ON);
slColRAMMode(CRM16_1024);
slCharNbg1(COL_TYPE_256,CHAR_SIZE_1x1);
slPlaneNbg1(PL_SIZE_1x1);
slMapNbg1((void*)NBG1_MAP_ADR,(void*) NBG1_MAP_ADR,(void*)NBG1_MAP_ADR,(void*)NBG1_MAP_ADR);
slBMPaletteNbg1(1);
slInitBitMap(bmNBG1, BM_512x256,(void *)NBG1_CEL_ADR);
slZoomNbg1(toFIXED(0.86), toFIXED(0.86));
slPlaneNbg1(PL_SIZE_1x1);
slTVOn();