In 1984, Commodore released the SX-64, a portable version of the C64. The SX-64 has the distinction of being the first ''full-color'' portable computer. The base unit featured a CRT and an integrated 1541 floppy disk drive. The SX-64 did not have a cassette connector.
Released in 1985, the C128 is a significantly expanded successor to the C64, with nearly full compatibility. It is housed in a redesigned case with an improved keyboard including a numeric keypad and function keys. Memory was enlarged to 128KB of RAM in two 64KB banks. A separate VDC graphics chip provided 80-column color video output in addition to the original C64 modes. It also included a Zilog [[Z80]] CPU which allows the C128 to run the [[CP/M]] operating system. The huge CP/M software library, coupled with the huge C64 software library, gave the C128 the broadest range of available software among all the 8-bit systems. The Z80 in a C128 runs at 4 MHz, but is throttled half the time to give the VIC access to the system bus, effectively making it execute at 2 MHz.
In 1986, Commodore released the Commodore 64C (C64C) computer, which was functionally identical to the original, but whose exterior design was remodeled in the sleeker style of the Commodore 128 and other contemporary design trends. The modifications to the C64 line were more than skin deep in the C64C with new versions of the SID, VIC and I/O chips being deployed—with the core voltage reduced from 12 V to 9 V. In the United States, the C64C was often bundled with the third-party GEOS GUI-based operating system. The Commodore 1541 disk drive received a matching face-lift resulting in the 1541c. Later a smaller, sleeker 1541-II model was introduced along with the 800KB 3.5-inch capable 1581.