Well I haven't come to the bottom of this but I think at least a part of the problem is related to overclocking since running FSB at 133 MHz spells trouble for most AGP cards. At least I found an ATI card that passes POST but I haven't run any tests to check overall system stability.

It appears that the board supports only 384 MB of RAM (unregistered) so that could explain the erratic behaviour when bigger modules are installed. It still doesn't explain why a supposedly 512 MB module is being detected as only 128 MB.

Cheers
SainT

I've experienced these ram problems my self... it's basically ECS that is the problem IMHO, cheap stuff... had 4-5 bat-a+ mobos , all various revisions... there is no rule of what it works, some mobos were good some no 🤣

Did another quick test this morning with a Pentium II clocked at 650@100. I used one stick of 256MB and two sticks of 128MB, all three of them PC-133. The board correctly detected all 512MB. I haven't got any more 256MB modules so I can't check, if adding more RAM would do anything...

I'll let it be until I can fine bigger modules.

Half-Saint wrote:

I'll let it be until I can fine bigger modules.

Bigger? 256MBx4 is the max for a i440BX chipset board, if all things cooperate. A 512MB module won't work.
Article:
http://homepage.hispeed.ch/rscheidegger/ram_bx_faq.html

Bigger meaning 256MB, I only have one 😀

440BX boards are picky, depending on the number of chips and the internal organization of the modules some sticks will not work, see here.

I tested all three 512MB modules that weren't being detected correctly in the 440BX board and they all work fine in a QDI Legend socket A board (VIA KT133A). I got another 256MB module but I can't test anything because I'm on vacation.

ECS board works fine at FSB 100 with 512MB of RAM. The moment you bump the FSB to 133, you start having problems.

Intermediate values can help with stability if the BIOS allows for it.