It was not uncommon to see modules with or without a parity chip (the ninth chip). This following module is non-parity because it has 8 chips.
Parity is an error checking technology that was very common with earlier memory modules. Most memory modules that are manufactured today use ECC (Error Correction Code).
When using the older memory modules with parity, the motherboard had to support parity. It was not uncommon for a motherboard to have the ability to use either parity or non-parity memory modules. It would only be required that the BIOS setting, to match the memory type.
