I tried Alien vs Predator, Batman Returns, Blue Lighting, Gates of Zendocon, Hard Drivin' and Xenophobe... all of them run fine (60 fps with properly graphic and sound)... the background scroll is "affected" by the screen tearing, but it should be a "known issue" (related to the double and triple buffer support).
PS: probably the throttle code was calibrated on the Dingoo CPU and it produced the slowdowns.