Hey

so I've got this motherboard from amoretro (picture taken by amoretro):

On board I can see
18x NEC D41256C-12 memory chips soldered
18x OKI M41256A-10 memory chips socketed

I assume there must be some kind of parity so when i calculate 32 x 256kbit = 8192kbit / 8 = 1024KB, the motherboard should have 1 Meg of memory, am I right?

BIOS is only showing 512KB. It is possible to set the memory size below 1M and above 1M in BIOS.
Below 1M, the biggest I can set is 640K and above 1M i can enter any value.
512/512 didn't work and 640/0 didn't work either (always says memory size error)

I have absolutely no clue how to configure that thing - may the socketed memory chips be faulty?

thanks for help!