All CPC models were based on a Zilog Z80 processor clocked at 4 MHz. Because a common pool of RAM is shared with the video circuits, the Z80 may only make a memory accesses every four cycles - which has the effect of rounding all instruction cycle lengths up to the next multiple of four.
The system came with 64 KB or 128 KB of RAM depending on the model (capable of being expanded to 512k576k). The machines also featured a standard 9-pin Atari-style joystick socket which was able to take two joysticks via a splitter.
===Video (graphics): modes, outputs===