A new development. I tried playing Diablo II now, and it just kept locking up before it would even start up. I tried using only one Voodoo 2 card even, and with one, it locked up, and with the other, the computer just rebooted.

I think both my cards are fried, and if that's the case, that really sucks.

So, have you tested the cards with any other games or benchmarks?

I did have an issue like this sometime ago. Windows detects the card and the drivers installed fine, and looks like everything is O.K....But fails to run any games. I accepted the card as broke. The cause I found? A bent pin on the VGA jump cable [must have touched another pin] and zap.

move them to different pci slots, retest.

The jumper cable is good, at least. Testing in other PCI slots will commence. I will report back when done.

The amount of memory reported in the control panel is a known bug. As long as SLI is working, you're fine. To make sure its working, try playing a game like UT in 1024x768 resolution, you wouldnt be able to do this with a single card. For installation help check this page.

I didn't know about the bug. Good to know. However, that doesn't fix my problem with the cards crashing my computer whenever any work is expected of them. Both cards have been tested in different PCI slots, and both cards lock up the computer with a blank gray screen (which didn't happen in their original slots). If I let the machine sit, it will eventually reboot on its own.

I don't own UT. Glide games I have are Diablo II, Redguard, Mechwarrior 2, Mechwarrior 2 Mercenaries, Quake and Quake 2. Perhaps others I have are also Glide games, but I don't know for sure at the moment.

In addition, I put different PCI cards into the slots the 2 Voodoo 2 cards occupied, and they work as they should, so the slots aren't bad.

try another power supply, and another pc if possible.

I don't have a spare PSU to test with, and the only other computer that has PCI slots isn't really set up just yet. I need to work on that.

Anyway, it would seem something got borked with the drivers. I uninstalled them, and installed the latest Diamond drivers again, and now it works. Insteresting to note that going into the display settings, one time it complained saying the cards didn't exist, and so the Monster 3D tab wasn't there, but I tried again, and it was there. Something isn't quite right it would seem.

EDIT: Well, even though now Diablo II will run, it locks up shortly after starting up. There is plainly something wrong, but I have no idea where. I'll need to see how they behave in my other PC, but this is a p3-500, and that's a p4-3.2GHz, so I don't know how well that will work.

You'd better download and install 3dfx's Glide2 SDK, Glide3 SDK and Glide Diagnostics Kit to find out 3dfx-related issues:

http://www.falconfly.de/reference.htm

Thanks, I was wondering if there was any sort of diagnostic utilities. These will help.

As an update. The idea to use a different PSU (which I'm unable to do) triggered a thought. After removing all nonessential parts (SCSI card, Zip drive, 5.25 floppy, USB 2.0 card) the voodoo 2 cards seem to be working much better. No freezing, or crashing. I still have to do a stress test, and I'll see what the diagnostics can tell me. But for now, it seems like it was a power issue.

Well, I downloaded the Diagnostic Kit. Detect.exe detects both cards just fine, and all the glide2x tests work perfectly. Almost all the glide3x tests complain about not having a valid window handle.
Is it possible that the cards could have been malfunctioning due to heat? I ask this because I had all 3 graphics cards right next to each other, and even with all the non essentials removed from my computer, 3dfx games still locked up. I spaced them apart now, and I've been running Diablo II for at least 1.5 hours without issue.

EDIT: After almost 2.5 hours, it finally froze. But nor the whole computer, just Diablo II, so I'm guessing something else could be at fault then. In addition, Redguard seems to be working well. MW2 3dfx hates my system for obvious reasons, but so does the Titanium version. Now to test my other Glide enabled games.

Yes, these cards heat up easily. You need to make sure the 2 voodoo 2 cards are as far away as possible from the other and from your primary card. I have my 2 Monster 3D II cards perfectly working on my B&W G3 because of the case fan blowing directly into them, as the case and motherboard themselves do not offer much room. You could also apply heatsinks on their main chips as well (boy, these could've fixed several freezings I had in the past with them).

And they heat up even more with a faster CPU feeding them. It might be a good idea to find some kind of cooling for them.

I suggest finding and putting some small (not enough to block the next pci slot) heatsinks for the three primary chips of both cards, and then putting a low RPM 80mm fan blowing down into the space between the 2d videocard and both voodoo2 cards. That should keep them all very happy.

I still suspect dirty power with your system, you should try to replace the power supply with a well made new one (check jonnyguru.com for reviews and ideas, but FSP is always a safe bet) and checking your motherboard thoroughly for crapping or bulging capacitors.

Thanks for the site reference. Finding a new ATX power supply that still includes a -5V rail could be problematic; hopefully they can help. I'll need to inspect my board closely to see if they're any cap issues.

I would suggest a modern atx psu and then adding an isolated 5v switching power supply and wiring it in inverse for -5v. Some of the better USB hub power bricks would be suitable.

-5V can easily be made from -12V...

A box like this likely won't miss -5v beyond the BIOS showing a wacky voltage reading with it missing. Unless you're planning to use some extra old ISA card (many ISA cards don't need it).

However, another thing to be aware of with modern PSUs and old boards is:
http://www.playtool.com/pages/psurailhistory/rails.html

The 5v to 12v rail shift isn't much of an issue, honestly, for the older systems because even a dual p3 tualatin rig won't take over 120w from the 5v rail, and dual p3 1ghz coppermines are right at 100w. Any single cpu system of the 5v rail era unless you use a massive array of old SCSI drives will be fine with a modern PSU.

As for -5v I hadn't even realized why the OP was wanting it - as swaaye says the -5v is a complete nonissue unless you have a specialized card that needs it.