The fact that both the GPU as well as the RAM stick get detected with a quarter of the total memory size makes me believe the system itself might be the culprit. You have tested these in multiple systems?

Some systems also only support DRAM to come in pairs or at at certain densities and are not able to allocate the full stick. This doesn't explain the GPU problem, though. But the card might be faulty.

RiP wrote:

For example, this 72-pin SIMM has eight NEC 4217400-60 chips that should be 16MB but detects as 4MB only.

The mainboard may simply not support the organisation of the memory module. It's totally normal that it then detects a different size. These chips are 4Mx4, the mainboard probably wants 1M, so it only detects 1/4 of the memory.

RiP wrote:

And the eight 4P4256DJ-M8 chips on the Trident TVGA8900C should be 1MB but detect as 256KB 😵

Detected by what? If the Trident is jumpered for 8-bit operation, it's auto-limited to 256 KB. Also, many older sysinfo tools always show 256 KB for VGA if they can't otherwise find out (or even try) how many video RAM is present.

derSammler wrote:

RiP wrote:

And the eight 4P4256DJ-M8 chips on the Trident TVGA8900C should be 1MB but detect as 256KB 😵

Detected by what? If the Trident is jumpered for 8-bit operation, it's auto-limited to 256 KB. Also, many older sysinfo tools always show 256 KB for VGA if they can't otherwise find out (or even try) how many video RAM is present.

Ah yes, the memory density is probably the problem here.

I found NSSI (v0.6.0) to have a very high chance of showing me the correct amount of graphics memory (at least in the vast majority of scenarios, depends on the system)

RiP wrote:

For example, this 72-pin SIMM has eight NEC 4217400-60 chips that should be 16MB but detects as 4MB only.

Probably mainboard does't support 16MB SIMMs. Try with Pentium era MB, not 486.

RiP wrote:

And the eight 4P4256DJ-M8 chips on the Trident TVGA8900C should be 1MB but detect as 256KB 😵

I have Genoa 8500VL 1MB VLB videocard based on CL-GD5426 chip. When I got it from the shelf, it showed 512 kilobytes. I replace all memory chip on it and then it shows 1 Mb. So, one of memory IC is bad.

derSammler wrote:

The mainboard may simply not support the organisation of the memory module. It's totally normal that it then detects a different […]
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RiP wrote:

For example, this 72-pin SIMM has eight NEC 4217400-60 chips that should be 16MB but detects as 4MB only.

The mainboard may simply not support the organisation of the memory module. It's totally normal that it then detects a different size. These chips are 4Mx4, the mainboard probably wants 1M, so it only detects 1/4 of the memory.

RiP wrote:

And the eight 4P4256DJ-M8 chips on the Trident TVGA8900C should be 1MB but detect as 256KB 😵

Detected by what? If the Trident is jumpered for 8-bit operation, it's auto-limited to 256 KB. Also, many older sysinfo tools always show 256 KB for VGA if they can't otherwise find out (or even try) how many video RAM is present.

I have lots of RAMs and motherboards. Only that single module has this problem 😕

Here's the video card:
https://stason.org/TULARC/pc/graphics-cards/I … -TVGA8900C.html
http://store.berkcom.com/Trident/JAX-8212B.php

I think you're right because it detects as 256K 8-bit but there's no jumper to set it as 16-bit 😵

RiP wrote:

I think you're right because it detects as 256K 8-bit but there's no jumper to set it as 16-bit 😵

Should be J4 - auto-sensing on/off.

derSammler wrote:

RiP wrote:

I think you're right because it detects as 256K 8-bit but there's no jumper to set it as 16-bit 😵

Should be J4 - auto-sensing on/off.

It didn't change anything...

Are you using it in an 16-bit ISA slot?

You still did not tell which program actually shows that it only has 256 KB.

derSammler wrote:

Are you using it in an 16-bit ISA slot?

You still did not tell which program actually shows that it only has 256 KB.

Yes.

Its video BIOS at startup reports: 256K 8-bit