It's not only "Sigo XXI" ones that may have it.
Also:
Zitieren:
There are (like with the Aquamarine RISC II) also models that run at 16 MHz, and thus score a bit higher in the BT-2630 test.
https://www.schach-computer.info/wik...ss_Wizard_IQ_V
This is a Zircon II clone, so I expect there may be newer version of Zircon II that have the 16MHz MCU.