And yes, TI calculators have indeed been improving, apparently.
The TI-84 Plus is a graphing calculator made by Texas Instruments which was released in early 2004. There is no original TI-84, only the TI-84 Plus, the TI-84 Plus Silver Edition models, and the TI-84 Plus CE. The TI-84 Plus is an enhanced version of the TI-83 Plus. The key-by-key correspondence is relatively the same, but the TI-84 features improved hardware. The archive (ROM) is about 3 times as large, and the CPU is about 2.5 times as fast (over the TI-83 and TI-83 Plus)[citation needed]. A USB port and built-in clock functionality were also added. The USB port on the TI-84 Plus series is USB On-The-Go compliant, similar to the next generation TI-Nspire calculator, which supports connecting to USB based data collection devices and probes, and supports device to device transfers over USB rather than over the serial link port.
Iircc the next level up was the TI 92 which could solve linear equations for you by default which was why they don’t let you use it on standard tests. Also cuz the Ti8x line can be quickly reset.
The TI-92 wasn’t allowed on standardized tests due to the qwerty keyboard layout making it be classified as a computer device in the US. The TI-89 has the same CAS functionality as a TI-92 Plus, but in a standardized test approved physical form factor.