The TI-83+ has 24 KB of available RAM, while the TI-86 has 96 KB RAM. Random access memory (RAM) is used for running programs and storing variables while in use. Applications, programs and firmware are stored long-term on the calculator using the slower read-only memory (ROM).
The TI-83+ display is made of 96x64 pixels, which can display 16 by 8 characters. The TI-86 has a larger screen made of 128 by 64 pixels, which can display 21 by 8 characters, five more characters horizontally than the TI-83+. A larger screen lets more information be displayed at once.
An advantage the TI-83+ has over the TI-86 is the built-in inclusion of a fully functional statistics package. If TI-86 owners want to make use of the statistics package they must download it from the Texas Instruments website and transfer it from a computer using a link cable.
The TI-86 has been discontinued and replaced with the TI-89 series, while the TI-83+ is still sold by Texas Instruments, as of May 2011. The TI-86 is generally a more advanced calculator than the TI-83+, having improved interactive graphing and dealing with vectors, complex numbers and matrices better than the TI-83+.