Hi , I did have the same problems until I did figure out this configuration that works fine to me with shenmue 1 and 2

I´m also using MasterChan777 version of null DC, runing on a laptop with intel core i7 160ghz and an AMD HD 6500 for graphics

NullDC Settings:
enable dynarec=on
accurate mode=off
enable CP pass=off
underclockFPU=off

PowerVR:
resolution : native or maximum (runs at about the same speed on both)
aspect ratio:borders
paletted textures:versioned
sort:per triangle (this solves the usual disaperance of ryo´s face when exit or entering a new area)
modifier volumes=off
Zbuffer=mode 2 (solves most of the weird shadow issues)
texture cache mode=delete invalidated
Vsync=Off

Aica=
Config= buffer size= 2048 , sync to audio =on, global focus= on, use hardware Mixing= off
limit speed and sync audio =off
sync audio =on
DSP emulation=off
mute CDDA=off


I Find that with this configuration both games run almost like in my dreamcast, and did complete them without any real issues, hope this config helps :D