Architecture
Later in the i386's production run, Intel introduced the i386SX, which was meant to be a low cost version of the 386 line. The SX series of chips was 32-bit internally, but had a 16-bit external data bus (in much the same way that the 8088 in the original IBM PC was a lower cost version of the 8086) and a 24 bit address bus; therefore, the processor could only address 16 MB. The original i386 was subsequently renamed the i386DX to avoid confusion. Neither CPU included a math coprocessor (most motherboards included a socket for an i387), though the naming would cause some head-scratching later when the i486 came in a DX variant that did include floating-point capability (which was physically present but disabled in early i486SXs).

i386SX
The i386SL was introduced as an alternative processor for laptop computers. The processor offered several power management options (e.g. SMM), as well as different "sleep" modes to conserve battery power. It also contained support for an external cache of 16 to 64 KiB. The extra functions caused this variant to have over 3 times as many transistors as the i386DX. The i386SL was first available at 20 MHz clockspeed [3], with the 25 MHz model later added. [4]

Embedded variants
The first PC company to design and manufacture a PC based on the 386 was Compaq, rather than IBM, which had been dominant until that time. IBM was offered use of the processor, but relied instead on earlier processors to which it had manufacturing rights. The success of the Compaq 386 PC played an important role in creating the PC "clone" industry, and to establishing Intel (and Microsoft) as central component suppliers to it.
From a business perspective, the i386 was significant because it was the first significant microprocessor to be single-sourced – it was available only from Intel Corp. Prior to this, the difficulty of making chips and the uncertainty of reliable supply required that any mass-market semiconductor be multi-sourced, that is, made by two or more manufacturers, the second and subsequent ones manufacturing under license from the designer. Single-sourcing the i386 allowed Intel greater control over its development and substantially greater profits in later years. However, AMD introduced its compatible Am386 processor in March 1991 after overcoming legal obstacles, thus ending Intel's monopoly on 32-bit 386-compatible processors. Later Cyrix offered Cx486SLC and Cx486DLC processors, pin-compatible with 80386SX and 80386DX respectively.