I've recently gotten interested in late AGP cards. Bought a Visiontek HD2600XT, and I'm impressed by the apparent build quality of that card. I will lean towards that brand in the future. It has top quality caps and a nice copper heatsink. There's even a heatsink on the back side of the card, but I noticed it doesn't actually make contact with the Rialto chip. That's one flaw.
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I haven't tested it in Windows yet. I tried it in linux mint 17.1, and it seems to work fine. Unfortunately, late AGP Radeons don't seem to have any linux support from ATI. I saw an old discussion thread where somebody from AMD/ATI was talking about such a driver being in development, but here in October 2015 there is still no listing for such a driver on their web site - only the Express versions. Apparently it never got done.
The open source linux driver for these cards performs so badly that it's not really usable for 3D in that OS. At first I didn't know if it was just because of WINE, but no, a slower nVidia card running the same game on WINE was much faster. Then I found the 'glmark2' OpenGL linux benchmark, and it confirmed the problem. The open source 'gallium' driver for the HD2600XT is just slow.
I always liked AMD, but I must say, their weak driver support for ATI graphics cards, especially anything more than a couple years old, is something that has damaged my opinion of AMD significantly.
Before that, I had bought a Sapphire X1950GT AGP card, but it doesn't work. It worked on the 2nd motherboard I tried it with, but none of 3 others, then it didn't work on that 2nd motherboard either. It's kind of frustrating to have a card that has worked once, because it means the problem must be some marginal thing that could be fixed, but I have no idea what it is. All the voltages seem to be good. The VRM is unusual, it doesn't have any large capacitors at all. The largest it has are three 100uF caps. I replaced the one that was accessible, and reflowed the molex connectors, and cleaned the edge connector, but it still won't POST anymore. A Dell BIOS logs an event saying there's an error initializing video.
This is why I hate buying used high end cards. They're so terribly prone to turn up dead.
Finally, I splurged on a 7800GS that was still sealed. I'm not even sure if I'll end up using it, but I always wanted one of those and getting one sealed means it should be in good condition. It's the fastest AGP Nvidia, short of some rare exotic cards. It's the kind of card that I'm afraid to spend much money on if they're used, because I'm afraid half of them will be faulty due to bumpgate and from the stress they've endured over their lives.
From what I've seen on eBay, it seems like the 2600XT cards are about the sweet spot for price vs performance. There doesn't seem to be much price differential between 2600 Pro and XT, even though online reviews show a major performance difference. The 3850 and 4670 are the ultimate AGP performers, but they get really expensive.
Just maybe a week ago, I was amazed to see that NewEgg still had new HD4650 AGP cards for sale. They were GDDR3 cards, unlike the typical DDR2 of all the others I've seen. With that RAM it seems they would perform almost as fast as the 4670. Then the very next day, they were sold out, surely for good.
