Those are 32Mbit/4MB SGRAM ICs and there are 8 of them, which means that the card does indeed have 32 MB of onboard memory.
If only 16MB are visible, then the card is faulty and only half of the memory is recognized (which is why the memory bus is also seen as being 64bit wide).
Looking at your photos, at first glance, I'm not seeing any physical damage. But things might look different under a microscope.

Most likely the card is defective in some way. I am 99.9% sure GeForce 256 DDR 16MB / 64-bit doesn't exist as an official product. I have the same memory chips on my Asus GF 256 DDR and it certainly is 32 MB / 128-bit.
I guess on your card either the memory controller in the GPU or half of the memory chips are dead. Perhaps on reboot the whole bus gets initialized and because of the defects you get glitches.

Once I had weird GeForce 2 Ti where also only half of the memory worked (32 MB / 64-bit in that case) but the PCB was fully populated.

Okey guys, after reading your comment that something must be defective I inspected the card. I found on the front memory chip, first on the left, right top corner some traces were blurred out and making bridges.
I reflowed the traces with some flux and now the card is seeing 32mb, and windows detect it as a 128bits 32mb GeForce DDR. All is fine when I reboot.

But it's not over, I ran some games, and some benchmark and the score is just above 6800 in 3dmark 99.
Same plateforme with tnt ultra gets above 7000.
I also kinda struggled to get it work in agp X4.

Chipset is a VIA appolo. I'm gonna try in a pentium 4 machine to see if it's the card or the platform !

Congrats 😀 Fixing your GF 256 DDR is great news.

If you currently run Pentium III on VIA chipset, then it is very likely a bottleneck. In 3dMark99 especially. For example on 2 GHz Athlon XP I got 11000 points.

havli wrote on 2023-07-29, 07:56:

Congrats 😀 Fixing your GF 256 DDR is great news.

If you currently run Pentium III on VIA chipset, then it is very likely a bottleneck. In 3dMark99 especially. For example on 2 GHz Athlon XP I got 11000 points.

Yeah thanks a lot for pointing at the ram being faulty.
Crazy how a little defect like this can impact a card. Pretty easy fix too .I just wonder if it left the factory like this?

Well you must be right regarding the performance. The more I read 99 reviews on the card the more I see that the performance I have are on par with what they have in reviews.
I think I was expecting a bit too much for this card/setup. In game performance are approximately similar to my voodoo 3 (10fps less in unreal demos) but the jump in quality is impressive. 32bits, high res texture, sharper graphics etc etc...
There is a bit more stuttering than with the voodoo, and direct 3d Unreal/unreal Tournament performance is atrocious which is weird to me (maybe a driver issue). But all in all, the jump in visual quality is amazing compared to a voodoo 3!

Some numbers :

800x600/32bits
Unreal: 50.8 fps castle demo
80 /90fps in game

Quake3: 63.6 q3dm6

800x600 16 bits:
3dmark 99: 6837 marks