Well, I already have trouble starting windows with the two gen older x800GTO.
What CPU are you using?

And the latest win9x driver is if I recall it correctly, catalyst 6.2

The last ATI cards supported under Windows 98 are the Radeon x700/x800/x850 using Catalyst 6.2 . The HD 2600XT is two generations later, so modded drivers are quite unlikely, to put it mildly .

Aebtdom wrote on 2021-06-13, 15:23:

Well, I already have trouble starting windows with the two gen older x800GTO.
What CPU are you using?

I have several PIII with 440BX and Via Apollo Pro 133 motherboards.

darry wrote on 2021-06-13, 15:50:

The last ATI cards supported under Windows 98 are the Radeon x700/x800/x850 using Catalyst 6.2 . The HD 2600XT is two generations later, so modded drivers are quite unlikely, to put it mildly .

Wich is kinda odd I think.
X800/850 XT are in the same "league" than 2600 XT. At the Nvidia side, I have a 6800GT which (shoukd) work with W98 (even being PCI-E) although having similar performance than the 2600 Pro.
Source: https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html

K-rnivoro wrote on 2021-06-14, 17:23:

I have several PIII with 440BX and Via Apollo Pro 133 motherboards.

Well, in that case anything faster than a geforce 4600 or an radeon 9700 is useless since you are totally bottlenecking with your cpu. You would have to go core2 or faster for this card.

K-rnivoro wrote on 2021-06-14, 17:31:

Wich is kinda odd I think.
X800/850 XT are in the same "league" than 2600 XT. At the Nvidia side, I have a 6800GT which (shoukd) work with W98 (even being PCI-E) although having similar performance than the 2600 Pro.
Source: https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html

They can be in the same "league" performance wise, but no driver support, kind of kills the whole Idea of being able to run these cards in win98 does it not?
And a r420/430 architecture on 110/130nm is nothing alike a RV620 on a 65nm tech. Let alone the core config etc... it needs specific drivers.

K-rnivoro wrote on 2021-06-14, 17:31:

Wich is kinda odd I think. X800/850 XT are in the same "league" than 2600 XT. At the Nvidia side, I have a 6800GT which (shoukd) […]
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darry wrote on 2021-06-13, 15:50:

The last ATI cards supported under Windows 98 are the Radeon x700/x800/x850 using Catalyst 6.2 . The HD 2600XT is two generations later, so modded drivers are quite unlikely, to put it mildly .

Wich is kinda odd I think.
X800/850 XT are in the same "league" than 2600 XT. At the Nvidia side, I have a 6800GT which (shoukd) work with W98 (even being PCI-E) although having similar performance than the 2600 Pro.
Source: https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html

Doesn't matter. ATI didn't make drivers for win9x for anything past the x8xx cards. The 2600 series cards are two generations newer.

Even if they would have made one - you really don't want a video card without support for 16-bit dithering in Win9x PC.

An HD2600XT is a great card for pushing an AGP system in XP, and it can accelerate HD video if you use the right player software. For win98 though it's too new to work as has been said.

For P3 motherboards like you listed, you should probably avoid "bridged" cards (which use a translator chip to make PCI Express GPUs communicate with an AGP slot). Bridged cards have hardware compatibility problems with P3 era chipsets (not sure about the 440BX but it definitely applies to VIA).
So even if you were to install XP to get the HD2600 working, you'd probably run into artifacts when using it in 3D with those motherboards.

I'd love to see a list of what chipsets ATI and nVidia actually tested and qualified their bridged cards to be compatible with. I don't know if such lists were ever released.

The Ti4xxx series and at least higher end FX cards are good if you want something powerful for DX8 and below on Win98. Not sure what's ideal on the ATI side.

If I remember correctly, the X300 and X600 were both just new labels slapped on old 9000-series cards, and only the X800 was actually a new architecture, so I'd expect catalyst 6.2 to work on Radeon X300 and X600 cards but not the X800

And yeah the HD 2000 series is definitely not happening.

K-rnivoro wrote on 2021-06-14, 17:31:

Wich is kinda odd I think.
X800/850 XT are in the same "league" than 2600 XT. At the Nvidia side, I have a 6800GT which (shoukd) work with W98 (even being PCI-E) although having similar performance than the 2600 Pro.
Source: https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html

Tom's Hardware is roughly categorizing performance, and that is not an indicator of compatibility. Old high end cards are designed differently from newer midrange / budget cards. And they are intended to run different software. Maybe an old iPhone is as fast as a Pentium 4... but the P4 runs Windows 98 and the iPhone doesn't, right? 😉

The X850 was launched as ATI's flagship part in 2004 and is the last ATI video card with [beta] driver support for Windows 9x. This is noted in the Catalyst 6.2 release notes. The 2600 was a low-mid product launched in 2007. Windows XP came out in 2001 and Windows Vista was out around the end of 2006.

I happen to have a Radeon X850 and I've tried using it Windows ME (it works). However it's kind of ridiculously / needlessly fast... I can get hundreds of frames per second in most Windows 98 era games by using a mere Radeon 9800 Pro (1600x1200 8xAA). IMO anything faster than a Radeon 9700 is better suited to Windows XP. Especially if you're using a Pentium III on a BX board (great combination for Windows 98!), you won't loose any performance by choosing an older video card.