homestarmake2008 wrote on 2021-05-18, 00:14:

GeForce 256 has AGP 4x. but voodoo 5 5500 has AGP 2x
why WHY

Not directly an answer to your question, but seeing as the 3D gaming performance is barely different between the Voodoo 5 5500 AGP and PCI implementations, AGP 4x would likely not have brought useful to the table .

Voodoo 5500 AGP vs PCI Benchmarks

https://www.anandtech.com/show/596

generally correct, but certain games do show significant differences in 1024x768 in conjunction with fast CPUs: https://www.3dcenter.org/artikel/3dfx-voodoo5 … econd-encounter and for much later games that can texture thrash, i'd imagine AGP to help somewhat too.

as for AGP 4x, VSA-100 can actually do it and the 4500 has the notch for it, but the 5500 (and 6000 prototypes, apparently) are 2x 3.3V only. maybe this is due to board complexity reasons, or some validation issues with AGP4x on those cards.

The 3dfx Voodoo5 5500 doesn't even have full AGP support - it's just a PCI66 card with an AGP interface. All commercially sold 3dfx AGP cards are PCI66 cards with AGP connector.

The only problem is that you can use a 3dfx AGP video card with almost none MB of the AGP 4x/8x generation, because the Voodoos require 3.3V which usually requires a board with AGP 2x compatability.

The next generation of Voodoos would have been fully AGP 4x/8x compatible, but - as we know - it has never been released.

kind regards
soggi

All commercially sold 3dfx AGP cards are PCI66 cards with AGP connector.

This statement is not accurate.

Voodoo5 is PCI66 (~AGP 1x) because of the dual chip design.

Reference 3dfx/STB Voodoo4 supports AGP 1.5V and AGP 4x transfer. PowerColor V4 supports AGP 3.3V and 2x transfer by default. Can be easily modded to run at AGP 4x 1.5V.

Voodoo3 supports AGP 3.3V with 2x transfer.

Banshee is PCI66 (~AGP 1x) I think.

havli wrote on 2021-05-18, 05:43:

This statement is not accurate. […]
Show full quote

All commercially sold 3dfx AGP cards are PCI66 cards with AGP connector.

This statement is not accurate.

Voodoo5 is PCI66 (~AGP 1x) because of the dual chip design.

Reference 3dfx/STB Voodoo4 supports AGP 1.5V and AGP 4x transfer. PowerColor V4 supports AGP 3.3V and 2x transfer by default. Can be easily modded to run at AGP 4x 1.5V.

Voodoo3 supports AGP 3.3V with 2x transfer.

Banshee is PCI66 (~AGP 1x) I think.

👆 This is very accurate, couldn't have made it more clear myself.

interestingly software still picks the v5 5500 up as an AGP 2x device with sideband addressing - guess 3dfx did that for compatibility purposes. the driver also has that AGP command FIFO setting.

havli wrote on 2021-05-18, 05:43:

All commercially sold 3dfx AGP cards are PCI66 cards with AGP connector.

This statement is not accurate.

Sorry for being a bit inaccurate...I forgot the V4 4500 AGP. PowerColor doesn't matter as I said "3dfx AGP cards".

Yes, the V3 is an AGP card, but it also doesn't support most AGP features.

It's also mentioned within the vogonswiki:

All AGP 3dfx cards use the port as a mere 66 MHz PCI port and do not utilize any of the special features that AGP offers. All AGP 3dfx cards are AGP 2x (3.3V) and must not be used in newer 1.5V slots. Only retail Voodoo 4 4500 cards are AGP 4x 1.5V capable. PCI and AGP versions of 3dfx hardware were considered to perform virtually identically with contemporary games, but testing has shown that later games can largely profit from higher bus bandwidth.

kind regards
soggi

The only ipotethical explanation was both the Avenger and the VSA-100 with the STB story were probably more like middle step graphic chips to take (too much) time to come back into the next-gen sector while mantaining compatibility "as a feature itself" but it couldn't work that way when mostly every features were basically working "in defence" or at the same level but late, compared to the alternatives. But at the end all those missed things were noticed and underlined by reviews even when frame rates were good for games of that time; they needed at least some of the features even if useless to mantain not only a decent speed side of the game rendering but also the marketing side that at that point was imho the main thing to solve.
The point that the V4 4500 were released (I don't remember if all of them or only some) with that "feature" shows that they began probably to move ahead but too late. It's incredible how many things, when seen with nowdays prospective were missed in those few years.

The Voodoo 5 doesn't make sense in a lot of ways, the 2x AGP thing is really not at the top of the list as far as I'm concerned.