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Intel later offered a modified version of its 80486DX in 80386 packaging, branded as the Intel RapidCAD.

This provided an upgrade path for users with 80386-compatible hardware.

The upgrade was a pair of chips that replaced both the 80386 and 80387.

Since the 80486DX design contained an FPU, the chip that replaced the 80386 contained the floating point functionality, and the chip that replaced the 80387 served very little purpose.

However, the latter chip was necessary in order to provide the FERR signal to the mainboard and appear to function as a normal floating point unit.

The CAD branding referred to the ease of upgrading existing OEM designs from 386 to 486 CPUs with rapid turn-around in the CAD room.