Dragon Ball Z Budokai 2: Core recommendations needed

Having yet another core selection problem in retroarch. DBZ2 Budokai .iso for PSX2 runs with a stutter. I have the ps2 bios in the systems folder and select the PS2 core in retroarch. Its definitely not a bad .iso as I had this problem with fotns.zip and simply selected the right core.

Any suggestions here? Am I selecting the right core? Are there any other auxilary files required?