Its CPU was a venerable Z80A running at 3.58 MHz, pretty standard for the '80s home computer, but its standardness was a major selling point. Due to the very small hardware differences between it and the Master System, porting was a breeze.
- Later models, starting with the MSX2, could be theoretically overclocked up to 6 MHz, and some implementations even provided a Turbo switch, but this mod was non-standard and could disturb some games. The MSX2+ had the official Turbo mode at 5.3 MHz, but this version was released only in Japan.
- TurboR machines, another Japan-only release, had the 7.16 MHz-clocked ASCII R800, a modified version of Zilog Z800, a 16-bit follow-up to the Z80. It used 4 times less clock ticks to process one Z80 instruction, so it was sometimes marketed as "28 MHz". While using an extended Z80 instruction set, the R800 was partially incompatible, in that some undocumented features were unavailable, so TurboRs had another processor, a real Z80, for backward compatibility.