AOpen AP43 User Manual page 29

There are two types of Cyrix DX4 CPUs: Cyrix DX4 with iDX4 pinout
and Cyrix DX4 with M7 pinout.
To determine the Cyrix DX4 CPU pinout, check the CPU label. A
Cyrix DX4 with iDX4 pinout has a "DX4 P/O" indication on the second
row of the lower CPU label. A Cyrix DX4 with M7 pinout does not
have this indication and the lower CPU label has only two rows. See
the figure below.
iDX4
pinout
indication
iDX4 Pinout
User's Guide
Hardware Setup
CYRIX DX4 CPUS
M7 Pinout
2-11