This section is concerned with the TI83 family of graphing calculators, which all use the same base processor chip — a Zilog Z80. There are five different calculators that are within this group: TI83, TI83+, TI83+SE, TI84+, TI84+SE, TI84+CSE, and TI84+CE. Each of these calculators has their own features and unique qualities.
Table of Contents

The TI83 Calculator
The TI83 is the oldest calculator in the group, being released back in 1996. It is designed to be an upgrade from the TI82, featuring a sleeker case design, more memory (27K bytes of RAM), and a faster processor (6MHz). It kept some of the features the same as the TI82, such as the screen size and being powered by 4 AAA batteries, to allow for backwards compatibility with the TI82. This means that while some of the TIBasic commands on the TI83 have a different syntax, at the core the TI83 can execute the TI82's TIBasic programs. Some of the differences between TIBasic for each calculator are how math is interpreted (implied multiplication versus regular multiplication) and commands that have an opening parentheses attached to the end of them (such as the trigonometry commands). When it comes to assembly programs, however, the TI83 cannot execute the TI82's assembly programs without some modification because of the processor upgrade. 
The TI83+ Calculator
The TI83+ was released in 1999, and it was meant as an upgrade from the TI83 with more memory and a faster processor. At the same time, it kept several features of the TI83 to maintain backwards compatibility: the case design, the screen size (16x8 home screen and 96x64 graph screen), and the link port. There are some major differences, however. The TI83+ cannot run assembly programs made for the TI83 because it uses a different format: there are three builtin commands, AsmPrgm, AsmComp( and Asm(, used for running assembly programs, while the TI83 has no such commands. The TI83 Plus uses a speedier 8MHz processor which is clocked at the same 6MHz as the TI83. The TI83 comes with 24K bytes of available memory builtin, while the TI83+ comes with 184K bytes of available memory: 24K bytes are RAM and 160K bytes are archive memory, or more commonly called "Flash" memory. Archive memory allows you to store data, programs, applications, or any other variables to a safe location where they cannot be edited or deleted inadvertently from a RAM crash. This creates a compatibility issue with TI83 TIBasic, however, because of the use of the Archive and UnArchive commands that are on the TI83+. 
The TI83+SE Calculator
The TI83+SE (short for Silver Edition) was the next calculator upgrade in the group. When it was released by TI in 2001, it became instantly popular because of its unique look and increased memory and speed. However, TI has since decided to stop production of it and focus on the TI84+SE calculator instead. The TI83+SE has now become somewhat of a collector's item. After seeing the success of the TI83 calculator series, TI decided to give their next TI83 series calculator a unique look to set it apart from the other TI83 calculators. The TI83+SE calculator look consists of a transparent silver case with silver sparkles sprinkled throughout. What really made the calculator shine, though, was that the transparent case allowed you to see what the internals of the calculator looked like without even having to open up the calculator. In addition to the unique look, TI also decided to upgrade the memory and speed. While maintaining almost complete backward compatibility, the TI83+SE features 128K bytes of RAM and 1.5M bytes of archive memory. It should be noted, however, that only 24K bytes of RAM are available to TIBasic programmers (you need to use assembly to access all 128K bytes). The TI83+SE uses a 15MHz processor, but it can also be made to run at the 8MHz and 6MHz speeds through assembly. 
The TI84 Plus Calculator
The TI84+ was released in 2004, and it was meant to be an upgrade of the TI83+. The TI84+ introduces a couple new things to the TI83 calculator series: a builtin clock and a mini USB link port. The builtin clock can be used in TIBasic by using the new clock commands that go with it, while the mini USB link port greatly increases the speed of linking the calculator to a computer. The TI84+ also improves upon the TI83+ in terms of memory and speed: 24K bytes of RAM and 480K bytes of archive memory; and a 15MHz processor (the same one that the TI83+SE has). The most obvious change that the TI84+ brings is a completely new case design. Gone are the slightly rounded edges and appearance; in its place is an almost circular look from the front, with the edges smoothly flowing around to the back of the calculator. 
The TI84 Plus Silver Edition Calculator
The TI84+SE was released along with the TI84+ in 2004, kind of like a TI83 calculator series package upgrade. The TI84+SE was meant to be an upgrade of the TI83+SE, and it includes the same upgrades that the TI84+ got. The two new innovations that the TI84+SE introduces are: interchangeable faceplates and a kickstand; these things are basically optional addons for your calculator. The interchangeable faceplate can be useful if you want to change the front look of your calculator. You simply purchase a different faceplate and swap it with the current faceplate. The calculator's initial faceplate is a light gray/silver. The kickstand is built into the calculator lid, and it allows you to set the calculator to four different viewing angles. Concerning memory and speed, the TI84+SE has the same amount of memory and speed as the TI83+SE. 
The TI84 Plus C Silver Edition Calculator
Initially leaked in 2012, the TI84+C Silver Edition (84+CSE) was officially announced in early 2013. The calculator was the first in the TI83/84 series to come with a color screen, hence the name Color Silver Edition. With the advent of color, several commands were added to utilize the new feature. The calculator has the same body as its predecessor, the TI84+/TI84+SE. A rechargeable Liion battery powers the battery, which can be charged in a dock or through the USB port. On the back, the calculator no longer has a snapin removable battery cover, but instead features a reset button and when pressed has the effect of clearing the RAM. Upon its release, some users noticed the speed difference between the TI84+CSE and other calculators. Because the calculator is powering the screen, the speed of the TI84+CSE is less than its predecessors. Still, the TI84+CSE brought color to the classroom, while remaining familiar to those who had used a calculator on the TI83/84 line. The TI84+CSE also has a larger array with which the Output( command can be used, a 26(x) x 10(y) grid. There is also a toolbar at the top that shows the basic settings of the calculator. As for changes with the graph screen, TI has created a graph buffer that effectively makes the graph screen much harder to use for games. 
The TI84+CE (and TI83PCE) Calculator
Announced and released in early 2015, the TI84 Plus CE (and TI84 Plus CET in some Europe countries) seeks to improve the qualities of the TI84+CSE. It is 30% lighter and 30% thinner than the TI84+CSE. The body of the calculator has been changed to a slimmer design. While the calculator still has the USB port for charging and data transfers, it no longer has the I/O port. The TI84+CE retains the same key map. Addressing the concerns of the slow TI84+CSE, the TI84+CE is faster. The processor has been upgraded from the usual z80 to the faster eZ80. In addition, it features more RAM and Archive space than any previous TI83/84 calculator. On the software side, quite a few behindthecurtains things have been taken from the TI68k series, making it a better suited (and easier) platform for native development. In France, the 84+CE is not sold, but is replaced by the better "TI83 Premium CE", which is exactly the same as the 84 Plus CE, but sold cheaper (around 90 USD) and with an exact math engine builtin (not a CAS, but exact values will be given when possible. For instance, √(90) will give 3√(10), instead of 9.4868…). Due to exams regulations there, it also has a PTT LED on top. In Europe (except France), the 84+CE is replaced by the "TI84 Plus CET", which is the same, but with the PTT LED on top, like the 83 Premium CE. 
Calculator Comparison
Model  Processor  RAM  ROM  Screen Size  Link Port  Clock  Release Date 

TI83  6 MHz  27 KB  None  96x64  I/O  No  1996 
TI83+  6 MHz  24 KB  160 KB  96x64  I/O  No  1999 
TI83+SE  15 MHz  24 KB (128 KB)  1.5 MB  96x64  I/O  No  2001 
TI84+  15 MHz  24 KB  480 KB  96x64  I/O+USB  Yes  2004 
TI84+SE  15 MHz  24 KB (128 KB)  1.5 MB  96x64  I/O+USB  Yes  2004 
TI84+CSE  15 MHz  21 KB (128 KB)  3.5 MB  320x240  I/O+USB  Yes  2013 
TI84+CE/83PCE  ~48 MHz  154 KB (256 KB)  4.0 MB  320x240  USB  Yes  2015 
Known ROM Versions
TI occasionally releases updates to the ROM version for each calculator, which either fix existing bugs, improve calculator performance, or add new commands and functionality. You can check the ROM version on your calculator by selecting the About option in the Memory menu, which is accessible by pressing 2nd MEM. See portability for a list of changes in functionality between the OS versions.
Model  Known ROM Versions 

TI83  1.02, 1.03, 1.04, 1.06, 1.07, 1.08, 1.10 
TI83+  1.03, 1.06, 1.08, 1.10, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 
TI83+SE  1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 
TI84+  2.21, 2.22, 2.30, 2.40, 2.41, 2.43, 2.53MP, 2.55MP 
TI84+SE  2.21, 2.22, 2.30, 2.40, 2.41, 2.43, 2.53MP, 2.55MP^{1} 
TINspire (84+ Emulation)  2.42, 2.46, 2.48, 2.54MP, 2.56 MP 
TI84+CSE  4.0, 4.2 
TI84+CE/83PCE  5.0, 5.0.1, 5.1.0.0110, 5.1.5.0019, 5.2.0.0035, 5.2.1.0042, 5.3.0.0037, 5.3.1.0058, 5.4.0.0034, 5.4.1.0052 (ChromeOS emulator), 5.6.0.0020 
PreLoaded Applications
Except for the TI83 which has no Flash ROM, all of the other TI83 series of calculators come with some preloaded applications for users to use. Since most of the applications are rather limited in use and scope, not to mention that they each take up 16K bytes or more of memory, most people end up deleting them off of their calculator to allow them to fit more programs and games. If you want to put them back on your calculator again, you can find them all on TI's website.
Model  PreLoaded Applications 

TI83+  Language Localization, Probability Simulation, Science Tools, StudyCards, Vernier EasyData 
TI83+SE  CellSheet, GeoMaster, Language Localization, Organizer, Periodic Table, StudyCards 
TI84+  Cabri Jr., Conic Graphing, Inequality Graphing, Language Localization, LearningCheck, LogIn, Probability Simulation, Science Tools, StudyCards, TI CBL/CBR, TImeSpan, Topics in Algebra 1, Transformation Graphing, Vernier EasyData 
TI84+SE  app4math, Area Formulas, Cabri Jr., Catalog Help, CellSheet, Conic Graphing, Fundamental Topics in Science, GeoMaster, Inequality Graphing, Language Localization, LearningCheck, LogIn, NoteFolio, Organizer, Periodic Table, Polynomial Root Finder and Simultaneous Equation Solver, Probability Simulation, Puzzle Pack, Science Tools, StartUp Customization, StudyCards, TI CBL/CBR, TImeSpan, Topics in Algebra 1, Transformation Graphing, Vernier EasyData 
TI84+CSE  App4Math, Polynomial Root Finder/Simultaneous Equation Solver, Vernier EasyData, Language Localization, Probability Simulation 
TI84+CE  App4Math, Language Localization, Polynomial Root Finder/Simultaneous Equation Solver, Vernier EasyData 
.