Playing a game in 3D requires more processing power than playing in 2D. If a game does not run smoothly in 2D then it is unlikely that you will get an acceptable result in 3D.
There are two main options for improving 3D performance:
1. Change the graphics settings in the game: typically games will enable you to change the resolution of the game as well as enable/disable advanced graphics settings like anti-aliasing. To improve performance, reduce the resolution and turn off or reduce the quality of various graphics settings in the game
2. Adjust TriDef 3D Ignition's performance settings: TriDef 3D Ignition has a performance menu in the OSD. The Virtual 3D mode can provide a significant speed increase. Alternatively, reduce the quality level of the current renderer in the performance menu.