Dubbed "Wicked Fast"[1] by its Product Manager, Frank Casanova – who came to Apple from Apollo Computer in Boston, Massachusetts, where the Boston term "wicked" is commonly used to denote anything extreme – the IIfx runs at a clock rate of 40 megahertz, has 32 KB of Level 2 cache, six NuBus slots, and includes a number of proprietary ASICs and coprocessors.

The extra pins are a separate path to allow latched read and write operations.

[2] The IIfx includes two special dedicated processors for floppy disk operations, sound, ADB, and serial communications.

[3] These I/O chips feature a pair of 10 MHz embedded 6502 CPUs, which is the same CPU family used in Apple II machines.

[5] Industrial Light & Magic upgraded their image processing hardware to the IIfx by the time Terminator 2: Judgment Day entered post-production.