Checked the FX 5200 with an ATX Power supply now, but it makes no difference. So that card just doesnt work on the board, no matter the power supply. A low end PCI card is still being shipped, so I will test if it works in general at all.

Kordanor wrote on 2023-03-16, 03:31:

Checked the FX 5200 with an ATX Power supply now, but it makes no difference. So that card just doesnt work on the board, no matter the power supply. A low end PCI card is still being shipped, so I will test if it works in general at all.

Sorry, but it seems you haven't read my post in detail.
It's not the power supply, it's the board.

Disruptor wrote on 2023-03-15, 14:43:

I guess that's the problem.
As far as I know, AT boards with both connectors do not provide 3.3 V supply on the PCI slots. They just support 3.3 V for the CPU socket only. But I may be wrong. Take a multimeter...
Well, you have to take a multimeter and trace the wires. Since mkarcher and me tried to run a Zotac GeForce 5200 PCI in a 486, we know that this card needs 3.3 V supply.

So you either need to mod the card or the mainboard at your own risk.
The way we gone was to modify the card with soldering a wire to directly connect it to the 3.3 V line.
Perhaps the 3.3 Volt to the PCI slots mod will work too with that particular card.

AT, by design, does not support 3.3V on anything, including CPU. Late AT-ATX combo motherboards may or may not support direct 3.3V passthrough from ATX connector. Proper late PCI video card will include signal converter, to avoid any issues.

The Serpent Rider wrote on 2023-03-16, 10:01:

AT, by design, does not support 3.3V on anything, including CPU. Late AT-ATX combo motherboards may or may not support direct 3.3V passthrough from ATX connector.

Would also be interesting to know which Graphics Cards do require 3.3V and which don't.

From chip support perspective:
On Nvidia side - up to GeForce 4 MX will work with 5V signal directly. May or may no boot due to BIOS issues though.
ATi dropped 5V support pretty early and late PCI Rage XL cards already had no support.
Matrox - no idea, because all relevant cards (pre-Parhelia) include converters. But some had PCI-PCI bridges, which are capricious with old chipsets.
S3, Savage 4 in particular, should be safe to use.
3dfx - all AGP cards up to Voodoo 3 will work with robust AGP-PCI adapter without signal conversion, but Voodoo 4/5 will not. Banshee and Voodoo 3/4/5 PCI will work.

Thanks a lot!
Will re-evaluate whether going this route makes more sense for me or replacing the board (and wiring the jumpers to switches and whatnot)

Apparently, some brands made 5V only (one notch) GeForce FX 5200 cards - https://www.newegg.com/prolink-geforce-fx-520 … N82E16814108129
Those should work too.

Just received the oldest PCI card I could find for cheap, so yeah, its definitely the issue with the "too new PCI card" and the voltage.
While these cards @theserpentrider mentioned exist, they are super rare/expensive. At that point you might as well replace the board...which is what I am going to do.

I just swapped my MGA G450 AGP-LP against a FX5200. 3D is a lot better and OpenGL has a working VSYNC.
I will probably stay on that FX-5200 because it has Amithlon-Support with Kernel 310 too. nice!