On second look, I also think the software filter the 3dfxgl.dll capture is applying isn't as nice as the actual Voodoo 3's filter, it seems blurrier like single or maybe double-pass horizontal (scanline) filter effects some console emulators use to fake composite video blur. The real deal is NOT that blurry and merely softens the dither (blends it more at high res, but at 640x480 the pixels are quite apparent) and is pretty nice on the whole, all things considered. (320x240 is grainy ... not that you'd ever need to run that low, but for comparison purposes the filter is mostly useless -slight softening, no real blending, but I suppose nicer on the eye than full unfiltered output; the bigger deal is the dither patterns on the Voodoo are easily demonstrated to be nicer than Riva 128 or Rage Pro -or Rage II- )
Given the Voodoo2/3 GPU seems to do all the necessary computation for 24-bit framebuffer output (just dithers the 24-bit pixel results to 16-bit for the output) it's a bit of a shame they didn't include a 24 or 32-bit color option. (limited max res and fillrate compared to 16-bit, but that's true for plenty of cards with 24/32-bit options or all cards as far as resolution goes -would be nice for SLI given each board only renders half the screen anyway, texture RAM ends up fully redundant, but framebuffer RAM doesn't)
Plus the lack of dither makes running at lower res less of a problem. (and the Voodoo's filter still acts as a modes pixel-edge AA effect) Color banding (and dither) are fairly noticeable in Unreal's fog effects where they aren't in the Software Renderer's 32-bit option (or even Rage Pro's 32-bit) though the Voodoo 2/3 obviously has other quality and performance advantages.
A bit off topic, but is it normal for Voodoo 3's to run really, really hot? (like passive heatsink /and/ back side of the card PCB burns to the touch) In this case a Voodoo 3 2000. It makes me nervous running in my P5A-B with it's limited PCI slots, butted up against the sound card or USB card I have installed. (an AGP Voodoo 3 would be in a nicer location, but ... ) I could always dig our the old Voodoo2 and run it in tandem with my AGP Rage Pro I suppose. (only have the 1, otherwise I'd consider going SLI -plus side of that P5A-B in spite of having only 3 PCI slots and being baby AT, none are blocked by the CPU)