Thanks for the info!
Good to know as also I might need help to fix DVI problem on my v4.

Hey hey hey! That's a sweet looking card you have there. Arguably better than AGP version in visual quality when using DVI.
Can you say what the fan model is? Also are those self-printed 3dfx stickers? I've been looking for a good 3-wire replacement for AAVID fans (7 mm thick as don't want to interfere with next slot).

Thanks for input.
I tried playing with all possible options options in V-control: Disabled sync to vertical refresh, disabled z-buff optimization, custom refresh rates.
All still result in same issue.
By the way, all the power cables are grounded in the surge protector.

As we know the artifacts/ flickering gets worse from 16-bit to 32-bit color, and with higher resolution. So it's almost like the more work you give card, the more trouble it has.

Right I'm suspecting more there is hardware issue, specifically something in the DVI circuit. The fact that VGA works perfectly including higher resolution with 32-bit color and Glide should indicate the VSA-100 chip is good, right?

I will plan to test the components around the DVI- maybe something went bad like one of those transistors?
I cannot really find others experiencing issues with the DVI chip SIL164CT64 but I suppose it's possible.

You raise a good point about overheating. I don't have strong reason to believe this but will try to check it out (I wish I had a thermal cam). Also do not have PCI-X to test.

Hey Obi-Wan,
Can I ask the brand/model of those fans that replaced the AAVID fans?
Are they 7 mm thickness like the original or 10 mm?
I'm trying to find a good 40 x 40 x 7 mm replacement for my noisy stock AAVID fans.

Thanks for suggestion.

I tried disabling Vsync (using 3dfx tools overclock menu- https://www.philscomputerlab.com/tools-for-voodoo-cards.html )

Unfortunately, no change with the DVI issue.

I have some short clips of issues:
Color Artifacts at 1024x768:
https://youtu.be/0sFW07fYtdM

Mouse flickering at resolution of 1152x864 or 1280x1024 (system often locks up requiring hard reboot).
https://youtu.be/9Lr3IJ8gJUk

By the way tried 16-bit, 256 colors - no difference.

Tried disabling the optimal refresh rate option 3dfx control panel utility- no change.

Thank you for the advice.
For the voodoo 4500 PCI, I only know of two main bioses for PC that support DVI:
- Version 1.18 which says "Voodoo4 4500 LCD" for bios string
- The custom version 1.18 that was modified by Rainbow (with the built-in editor).

What bios did you use?  
V 1.15 does not seem to have DVI.

Greetings.
I have a voodoo 4 mac/dvi that I finally got around to flashing for PC. I used the voodoo4 4500 pci 1.18 dvi bios available at:
http://www.tdfx.de/ger/dload_bios_v5.shtml
(same bios available at 3dfxbios.cl-rahden.de).

The card works perfectly in ALL aspects (glide, 2D through VGA port) except for 1 main issue- the DVI output begins to act up beyond a resolution of 800x600. The higher res I go, the more issues crop up. The colors look right though.
- At 1024x768 - the screen may flicker after several seconds, and there are slight reddish artifacts scattered about.
- At 1280x1024, the screen flickers more, the mouse cursor continually flickers and mouse cannot be moved.
- Eventually, at higher resolutions, it crashes.
I've tried several different DVI cables (dual-link, single-link DVI-D) with no difference.
Tried different versions of voodoo drivers (e.g. 1.04.01-beta, 3dhq 1.09 beta10) to no avail.
Ran every graphic card diagnostics software you can think of (memory test etc) which all checks out.

I am thinking either the bios or driver may be the culprit (as early DVI implementations were known to be problematic, see http://www.playtool.com/pages/dvicompat/dvi.html#pixelclock), but cannot confirm.

I suspect the voodoo 4500 PCI w/DVI bios that has circulated around is that of a prototype card. It is labeled as "Voodoo4 4500 LCD" when examining in Tdfx bios editor, something that is almost never seen for voodoo card (not even for v5 5500 dvi). Also as far as I know, only other time "LCD" was mentioned in bios string was prototype voodoo 4500:
http://www.3dfxzone.it/enboard/topic.asp?TOPIC_ID=377&whichpage=1
(bios screen here https://web.archive.org/web/20031119064033/sloomy.kolayweb.com/DSCN0061.JPG )

As I was hoping to try to keep the card closer to stock bios, I haven't tried that custom v4 dvi bios w/ editor screen (made by Rainbow, version 1.18B04).

I'm wondering if anybody with voodoo 4500 dvi has had similar issue with DVI output? If so any suggestion?
Should I have reason to believe there is a hardware issue in my card?
Thanks in advance.