I may be remembering wrong, but I do recall a small number of ATI cards that had been bridged from AGP to PCIe, to fill the manufacturing gap during the transition from old to new. I think they were cards used under XP though, but I'd have to dig back to see if any of them were 98 compatible GPUs.

There are pcie FX series cards, Quadro cards, Geforce 6 and 7 series cards. And the x850 on the ATI side.

RetroGamer4Ever wrote on 2021-10-01, 23:12:

I may be remembering wrong, but I do recall a small number of ATI cards that had been bridged from AGP to PCIe, to fill the manufacturing gap during the transition from old to new. I think they were cards used under XP though, but I'd have to dig back to see if any of them were 98 compatible GPUs.

No, I think you're right.

There were AGP and PCIe cards that got backports to the previous slots.

And budget cards of both AGP/PCie got PCI versions, too.

This was either possible via bridge chips or by using some trickery.

To understand how this was possible, let me explain how AGP works in a simplified way:

AGP essentially is a special-pupose PCI slot that runs at twice the speed, 66MHz, and has a GART.
Whereas GART is some sort of memory managment unit.

PCIe on the other hand is a serial link which behaves like a PCI bus software-wise.

So in essence, both AGP and PCIe are relatives of good old PCI.
And if certain features are being sacrificed, they can still act like it.

ODwilly wrote on 2021-10-02, 00:47:

And the x850 on the ATI side.

There's also the lamer but not all that lame x300, x600, x800... the x300 does okay I think on stuff near 2000, but that's based on memories of integrated x300 in a laptop playing NFS3 and similar on XP. It's 9600ish so plenty fast for about pre2002 then runs out of steam more towards the mid noughties.

The funny thing with the early Nvidia PCI-E cards is that in the 81.98 driver package only the AGP versions are listed.
To install this driver, one has first to unpack the driver .exe using Winzip, then edit the NVAGP.INF file to include the PCI-E cards PCI ID (at two places, one time in the PCI ID section and the features/resolutions section).
After this is done, the PCI-E version will install fine when running the Nvidia Setup program.

I had to do this twice recently, one time for the NVS280 PCI-E, and then again for the GeForce PCX5750 😀
Both support old DOS games as fine as DX 9, and run nicely on modern mobos.
So, no need for old slow AGP mobo garbage 😀

X300 and X600 are identical chips. Latter had better memory and chip default clock. Although only X600Pro/XT with mild overclocking can play shader games of Xbox era somewhat decently.

That said, X600XT should be faster than GeForce 4 Ti 4600 in most cases - https://www.youtube.com/watch?v=Z5T9ecasOVM

I may be remembering wrong, but I do recall a small number of ATI cards that had been bridged from AGP to PCIe

Nvidia packaged GeForce FX 5700/5900 with a bridge for PCIe and later made GeForce 6800GT/Ultra (and Quadro counterparts) with the same bridge, but on one PCB. ATi never bothered with such weird transition and just made new chips that support PCIe.

A lot of good info here, so thanks to all!

At this point I'm leaning to just finding an old P4 board with AGP 4x\8x and SATA capabilities.

Anyone know how 98 SE is in general with true AGP 8x cards or are we realistically looking at 4x with the OS\drivers\rarity\cost\etc...?

It will work, AGP speeds are usually inconsequential.