Before comparing the TI calculator models, it is best to know exactly all of the models available. They are, in no particular order: TI-Nspire TI-84, Plus Silver Edition, TI-84 Plus, TI-83 Plus, TI-89 Titanium and TI-Nspire CAS.
All of the calculator models are accepted for use for SATs, APs, PSATs, and Praxis. However, the ACT test does not allow the TI-89 Titanium and TI-Nspire CAS models. The primary reason for this is their saving files function, as students could use this for potential cheating. This also holds true with standard classroom use.
The TI-84 Plus, TI-83 Plus and TI-89 Titanium models offer no extended features beyond the core calculation functions. The TI-84 Plus Silver Edition offers extra features, such as downloadable test prep questions, and comes with an organizer preload. The TI-Nspire series offers the most features It is rechargeable battery-ready. It offers a built-in mouse; save, edit and review filing system and a four-way split screen.