The Turbo co-processor fits internally into a Master 128, although it can be used externally in a suitable adapter such as the Watford Co-Processor Adapter and connected to a BBC B instead.

The co-processor uses a 65C102, a superior version of the 6502 processor which has several more instructions and runs at 4MHz, meaning it is twice as fast as the Beeb's CPU, and half as fast again as the processor in the original 6502 cheese wedge second processor.

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