PCI cards are obviously an option
https://www.youtube.com/watch?v=TAcMvJSMWIs
he also tested PCIe x1
https://www.youtube.com/watch?v=yNEge5r6-mg
The fastest card would either be a GT 710 (for PCI x1) or GT 520/610 (on both PCI and PCIe x1), and afaik someone even made a GT 640 on those old slots. If you want a Radeon, there is the HD 5450
Below that some 9500 GT also came in PCI
Any of them will be much better than the GMA 900 on the 915G chipset, which might have pixel shader 2, but no hardware T&L and no hardware vertex shaders. In theory DX9 capable, but no speed at anything DX7 and above.
I found some old review of the thing:
https://www.anandtech.com/show/1413
Warcraft 3 will run okay, they got 47.8 fps in 640x480 with a Pentium 4 3 GHz, UT2004 in 640x480 on lowest settings gets 37.5 fps
Here is another one:
https://www.computerbase.de/2005-05/test-turb … hypermemory/15/
Half Life 2 runs just below 20 fps in 800x600, Max Payne 2 pushes at least close to 40
Then obviously opening up the back of a x1 slot and putting a bigger card in.
Mechanically supported, but x1 only offers 25 W, while x16 offers 66 W on the 12 V rail and allows for 75 W total, so a full card will most likely go out of spec there.
The biggest issue is the lack of both, PCIe x16 and AGP.
But if it's just for properly old games, any card will do. Could grab some old TNT2 or Mach 64 or ET4000 for that kind of stuff. Some of it would probably even run better on them.
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