Once in a while a lot of questions come by about voodoo cards so i decided to make a list with some info. Might be useable for new people that want to use one.
These cards have good direct3d support but their strongest feature is glide ofcourse, 3Dfx's own api for 3d games.

Each voodoo card has it's own pros and cons, So imho the best voodoo card doesn't exist. You have to make some choices and based on that you can decide which card suits your needs.

This is not about all the features of the cards, but more about the problems that might occur and hopefully a solution for them.

For a lot of good info about every card, also check the wiki: http://www.vogonswiki.com/index.php/3dfx
Also a very good source for 3dfx is falconfly (also a great source for drivers): http://www.falconfly.de/

A thing about multiple voodoo cards in one system:

You can install for example a voodoo2 and a voodoo3 in one system, there are people that have even three cards working.
Just make sure you install the add-on card driver first (v1/v2) and the card that handles 2d also last.
This way windows picks up de drivers from the 2d/3d card first and everything should work fine.

When a game does not pick up for example the v2, put this card's driver directly into the game's directory.

I have a v2 and v3 agp in a p2-450 system using 98se. Both cards work perfectly. Testing 3dmark99 i can select both cards and run them so in direct3d they also work.

A voodoo3 pci and for example a v5 agp can also be done: Just hook them up to a vga switch (or switch cable by hand). Select in the bios the one you want to use (pci or agp as primary vga).
When booting windows it should pick the right card (after driver installation ofcourse).

A thing about heat:

We like to push 3dfx cards to the limit and use them in our retro systems with the fastest cpu's possible sometimes simply because we can. Cpu's weren't that fast when these cards were released and a lot of them are passively cooled. They do get hot and when pushed by a fast cpu they get even hotter so adding extra cooling in the form of a heatsink/better heatsink and a good fan can make your card more stable and/or expand the
lifespan.

About agp voltage:

Voodoo banshee/3/5 agp cards only work with 3,3v agp slots so be careful with newer boards. socket7/slot1/slotA/s370 boards are usually fine. for socket A the limit seems to be a board with via kt333A chipset (but still check it). kt400/nforce and higher are not compatible with 3,3v agp cards.
Intel boards for p4 cpu's are not compatible at all. Only some p4 boards with SIS chipsets are know to work (check before trying).

Exception is the the voodoo4, but check before trying. from falconfly:

All Banshee, Voodoo3 and Voodoo5 AGP Cards are 2xAGP 3.3V only!
Do not use in modern 4x/8x AGP 1.5V only Motherboards!
Failure to comply can cause damage to both the Card and the Motherboard!
Consult your Motherboard manual for 2xAGP 3.3V support before use!
Only the retail 3dfx built Voodoo4 4500 AGP is 4xAGP 1.5V capable.
(the Powercolor Evilking Voodoo4 and the rare 3dfx Voodoo4 4500 "L" Shaped variants are confirmed to be 2xAGP 3.3V only)

A thing about agp voltage regulators:

Always be careful with cards from this era and older agp slots, some boards were not prepared for these cards. Info from falconfly:

AGP voltage regulator notes: There is a problem with the combination of older motherboards and newer AGP graphic cards. This is due to the fact that some of the early AGP motherboards used a linear regulator to control the power supply to the AGP slot. Linear regulators can supply at most 2.5A of current, while the switching regulator used on newer motherboards can supply up to 6A at 3.3V. When these motherboards with linear regulators were produced, the average consumption of a graphics card was 1 to 2A, making a supply of 2.5A more than sufficient. Since then, graphic cards have developed and currently the average consumption is between 4 and 5A. This is no problem for motherboards using a switching regulator, but older boards with a linear regulator may run into issues such as overheating, burnouts, and lockups.

If you want to be on the safe side: check your voltage regulator or use a voodoo pci card on these boards.

About agp vs pci performance:

Imho there is very little difference in speed since all voodoo's do not use agp features. They do benefit from the higher busspeed so with very fast cpu's there might be a difference.
Only noticeable difference i saw was with the voodoo5: On a p3 tualatin 1400mhz the agp version was 10-15% faster as the v5 pci. this will depend on quality settings and resolution as well as AA settings.

The agp version is the card to have when your motherboard has problems with other agp cards. Super socket 7 boards with agp slots (based on via and ali chipsets) are known to be problematic with some agp cards, and also some via based slot1/s370 boards can have agp problems.
The voodoo cards do not use most agp features so they can be more stable on these platforms.

A few things to check when a card is not working:

Check all the small legs on the 3dfx chips, i have seen a few cards where these legs touched each other and the card didn't work. I have one v1 and two v2's that had this and now they work fine. Simply gently separate the legs with a very thin blade.
Try a different pci slot, i had some occasions where this simple solution did the trick.
Try cleaning the contacts of the pci/agp connector.
Try different drivers.
Try another computer.
Change the caps, it might come to life again.

I also have a few 3dfx pci cards that simply didn't work in an open testbench. With the cards ''hanging'' in the pci slot they didn't display anything. When held straight up or secured in a case they work perfectly fine.
So always try that when you get a black screen in an open testbench.

About v1/v2 pass-trough cables:

If you don't have one you could use a vga extension cable. These are much longer so they could degrade the image quality but they can be found pretty easily.
Or simply make your own cable.

Some info per card,

Voodoo graphics (voodoo1):

3d only.
Max. resolution 640x480.
only 16bit color.
The slowest but most compatible card, especially for the early dos based glide games. Some people (including me) had problems with some games when using this card in a system with a p3-400mhz or higher.
This card doesn't always like fast cpu's or high fsb systems. It is maxed out around p2-300mhz anyway, so if you have problems or the card doesn''t work at all: try a slower system.

If after installing the drivers in win95/98 direct3d does not work: install directx6.1 and after that install the oldest Diamond monster 3D drivers first. Check if direct3d works with dxdiag. Now you can install any 3dfx v1 driver you want. It solved my problems everytime.

Voodoo1 and voodoo2 image quality tends to be a bit blurry, this is mostly because of the pass-trough cable. It can get a little better by using a shorter and/or thicker cable. Best image quality can be had by not using the pass-trough cable at all: simply use a vga switch or 2 monitors and switch when starting up a game.

Phil made a great topic about v1 and v2 scaling on a socket 7 system Socket 7 Voodoo vs. Voodoo 2 CPU Scaling
He also made one with faster systems: 3dfx Voodoo vs. Voodoo 2 - This might help you make a choice!

Voodoo rush:

Combined 2d/3d card.
Max 3d resoltion 640x480.
only 16bit color.
This card is far less popular. It is less compatible with the oldest games and slower than voodoo1. For early games there are patches that fix most of the problems.
They came in 2 versions, one with alliance chip for 2d and one with Macronix 2D chip. the last 2d chip seems to be a bit slower.
I have 2 alliance versions and both gave display corruption in windows. It seems that some drivers clock the alliance chip too high. You can fix this in the registry by simply clocking the alliance chip a bit slower.

You can find the registry setting here: HKEY_LOCAL_MACHINE, SOFTWARE\Alliance Semiconductor\Driver\HW Acceleration Settings, MCLKFrequency

Setting it from 72 to 60 will most likely fix the problem.

These cards also didn't like fast systems when i tested them, so the same as with voodoo1, if you have problems try a slower system.

Voodoo2:

3d only.
Single card max. resolution 800x600, in sli 1024x768.
only 16bit color.
One of the most popular versions, up to 3x faster than voodoo1 .
It is a little less compatible with the oldest glide games but a lot can be fixed with the right driver settings and patches.
No problems with fast cpu's as far as i know. EDIT: There can be some problems when using p4 systems. Using latest drivers or 3rth party drivers might solve this issue.

Vetz made a great topic about compatibility of these cards so when you are having problems with games be sure to check this out : Voodoo 2 DOS Glide compatibility matrix

V2 can be used in sli: 2 cards connected together with a sli cable. If you don't have a sli cable the vogons wiki provides perfect info on how to make your own: http://www.vogonswiki.com/index.php/How_to_ma … doo_2_SLI_cable

The latest drivers allow sli mixed with two cards of different brands. This does not always work so for best compatibility 2 identical cards are the best solution.
In my experience Diamond and Creative cards are harder to mix, other brands seem to be more compatible with eachother. But it is simply trial and error so just pick 2 identical ones if you can.

Sometimes you can mix an 8mb v2 with a 12mb v2 but again: trial and error. If this configuration works it will work as 2 voodoo2 8mb cards.

If you have problems with a sli setup in certain games: try switching the 2 cards or try different pci slots. I had one occasion where most games worked fine but i had a black screen in one. When moving the cards to the last pci slots the game worked fine (and still did the others).

Voodoo1 and voodoo2 image quality tends to be a bit blurry, this is mostly because of the pass-trough cable. It can get a little better by using a shorter and/or thicker cable. Best image quality can be had by not using the pass-trough cable at all: simply use a vga switch or 2 monitors and switch when starting up a game.

Phil did a great project about V2 and v2 sli scaling on 100mhz to 1400mhz cpu's. All data collected in a single pdf: Phil's Voodoo 2 (and SLI) processor Scaling project - 65 pages, 875 benchmark results

Voodoo banshee:

2d/3d card, much better image quality versus v1 and v2, and higher resolutions.
comes in agp and pci versions
16bit color only
Can be slower or faster when compared to a single v2, this depends on the game. Banshee is clocked higher but is slower at multi-texturing.
I don't know how it reacts to fast cpu's, so try a slower system when you have problems.
Compatibilty with older glide games should be okay when applying the right drivers/patches. some games work when using patches that were made for voodoo rush.

Voodoo3:

Combined 2d/3d card, much better image quality versus v1 and v2, and higher resolutions.
Voodoo3 is about as fast as 2 v2's in sli mode.
Only 16bit color.
These cards are available in pci and agp.
Less compatible with older glide games compared to v1 and v2. Most of them you can get working with the right driver setup and patches.

Vetz made a great topic about it: Voodoo 2 DOS Glide compatibility matrix Voodoo3 compatibilty matrix is found on the second page of this topic.

If you want to know about v3 cpu scaling look at phils v2 scaling project. v3 2000 is a little slower, v3-3000 is about equal and a v3-3500 is a little faster when compared to v2-sli:
Phil's Voodoo 2 (and SLI) processor Scaling project - 65 pages, 875 benchmark results

The voodoo3 3500 can be had as a 3500TV version. It has a tv-tuner on board and does require the dongle that came with the card to connect it to the pc. the dongle has the connections for vga and tv-out,so the card can't be connected without the dongle.

Voodoo4 4500:

2d/3d card.
As fast or a little faster as a voodoo3 3500.
Supports 32bit color.
Comes with a fan on the heatsink.
Comes in pci and agp versions.
Not so easy to get to work with the oldest glide games, i believe v1/v2/v3 are much more compatibel.

A big plus for this card is that it can use 2xAA when a game isn't too demanding (AA cuts performance in halve).

Cpu scaling up to about 1ghz at 640x480 . When 2xAA is used a p3-450mhz will probably max it out.

Voodoo5 5500:

The top dog (well, atleast for most people wich can't find/afford a voodoo5 6000 🤣 )
requires a molex connector for powering the card.
Dual gpu card and basicly 2x voodoo4 4500 on a single board.
comes in agp and pci versions.
Supports 32bit color.
Support 2x and 4xAA.

There is a mac edition (pci only) that can be flashed to work on pc. This is the only card that has a vga and dvi connection, and dvi works on pc when flashed with the right bios.
For the flash tool and bios file use this link: http://www.3dfxzone.it/dir/3dfx/voodoo5/bios/tools/, instructions are with the flash tool and on the web. Use it at your own risk.

In my own tests the agp version can be 10-15% quicker as the pci version when paired with a fast cpu (i used a p3-1400).

Here is a link about voodoo5 cpu scaling: http://nightstormer.tripod.com/voodoo_article6.htm

I will add any good info/tips when they come along. And please, correct me if i am wrong about something!!