Chess computers with F8 CPU and XTAL are:
- Compuchess - 1.78MHz
- Boris - 2MHz
- Savant - 4Mhz/2 divider (sub-cpu, handling keyboard & lcd)

No XTAL:
- Delta 1 (2MHz, LC circuit measured)
- Conic Computer Chess/Master I (2MHz, LC circuit measured)
- MK I (approx 2.18MHz measured)
- Chess Traveler/Pocket Chess (3MHz/2 divider, measured)
- Boris Diplomat (3MHz/2 divider, guessed)
- CP2000 (2MHz guessed)

with "measure", in this case I mean electronically measure the CPU clock pin with an oscilloscope or gadget.