PC@LIVE wrote on 2021-07-02, 20:54:
Returning to the PC with BEK V429S, the chipset is Opti, the memories I photographed and they are double-sided, I installed them on the central banks, so 2 and 3 while the one and the four (one is the 30PIN one) are empty .
OK, so this is just as I expected. It's good that it works this way, even if your configuration is not listed in TH99 / UH19.
PC@LIVE wrote on 2021-07-02, 20:54:
From the photos I can read in a memory a written on a sticker, RAM2MX32S70501, this has 16 chips (8 per side) signed TI-70 tms44400dj, the other has 4 large chips (2 per side), but I cannot read the abbreviations on the chips.
The TMS44400dj is a 4MBit chip in a x4 organization. This means it has 1M of addresses and stores 4 bit at each of those addresses. Take two of those chips, and you get 1 MByte. You can build 1MB 30-pin SIMMs without parity exactly that way. Each side of the 16-chip SIMM is basically identical to four of those 1MB 30-pin SIMMs, just in an easier to handle form factor. This is a pattern that always holds: A single "side" of a PS/2 SIMM behaves very similar to a bank of four 30-pin SIMMs.
The other SIMM obviously has 16MBit chips (the next generation - at that time, each generation of memory chips had 4 times the size of the previous generation) in a x16 configuration, so two of them are enough to make the 32 bits your need for each side. 16 MBit in a x16 configuration means the 16 MBit are distributed over 1M addresses, and each of these addresses stores 16 bit. So a single of these chips behaves like a 16-bit bank made out of two 1MB 30-pin SIMMs.
Notice how I always write "behaves like 1MB 30-pin SIMMs". Your chipset is maxed out at 16MB, as long as you only use modules that "behave like (a quadruple of / an octuple of) 1MB 30-pin SIMMs". To get to the full 64MByte the chipset supports, you need modules that in total behave like 16 30-pin 4MB SIMMs. Your options for modules that behave like 30-pin 4MB SIMMs are:
4 4MB 30-pin SIMMs
a 16MB PS/2 SIMM that behaves the same as 4 4MB 30-pin SIMMs
a 32MB PS/2 SIMM that behaves the same as 8 4MB 30-pin SIMMs
4 30-pin SIMMs + 3 16MB PS/2 modules is a configuration explicitly listed in your mainboard documentation. 2 32MB PS/2 modules in the same slots you currently have the 8MB modules in is also very likely to work. And of course, you don't need to go all the way to 64 MB, but you can stop at 32MB (e.g. from one 32MB or 2 16MB PS/2 modules).