Editing Acorn Archimedes A540 (section)

=== Processor ===
The A540 featured an ARM3 processor on a replaceable CPU card. Initial models shipped with processors running at 25-26 MHz, though variants existed running at 30 MHz and 33 MHz. The 26 MHz version used a 52 MHz oscillator, while some machines used 60 MHz oscillators for 30 MHz operation. The ARM3 included 4 KB of cache memory, providing substantial performance improvements over ARM2-based models.

The CPU card could accommodate an FPA10 (Floating Point Accelerator), with FPA11 also being compatible with later variants. The 33 MHz ARM3 CPU with FPA10 combination represented the highest performance configuration available. The ceramic ARM3 processors used in some machines could be overclocked, with reports of stable operation at up to 40+ MHz.