Probably it sets the clock rate differently? It's quite normal to get corrupted 2d with these cards, as they are overclocked by default.

I'm not experienced with these cards, but aren't there versions with different 2D chips? Might those need different drivers?

Just go in the windows registry and change the Alliance frequency a couple mhz lower (try like 5mhz, otherwise try a bit more). This will not affect your 3d performance but a lot of driver seem to overclock the 2d part a bit and it cannot handle that.

Worked fine with my rush cards...

for more details look at my little guide : a 3dfx voodoo guide

meljor wrote:

Just go in the windows registry and change the Alliance frequency a couple mhz lower (try like 5mhz, otherwise try a bit more). This will not affect your 3d performance but a lot of driver seem to overclock the 2d part a bit and it cannot handle that.

Worked fine with my rush cards...

Why if all worked fine with dual planar driver?

Maybe that driver does not overclock the card? And dual or single, the hardware (and chips) are the same so that's probably why it works anyway. But the cards are build differently so maybe there are some timing differences or something and the card may be less stable in the long run?

Don't know, just guessing!

meljor wrote:

Maybe that driver does not overclock the card? And dual or single, the hardware (and chips) are the same so that's probably why it works anyway. But the cards are build differently so maybe there are some timing differences or something and the card may be less stable in the long run?

Don't know, just guessing!

From promtn.inf :

dual:

1[Driver.AddClock]
2HKEY_LOCAL_MACHINE,"SOFTWARE\Alliance Semiconductor\Driver\HW Acceleration Settings",MCLKFrequency,,58

single:

1[Driver.AddClock]
2HKEY_LOCAL_MACHINE,"SOFTWARE\Alliance Semiconductor\Driver\HW Acceleration Settings",MCLKFrequency,,72

There you have it. 72mhz is also too high on my cards and if 58mhz is the original default setting than it's no wonder 72mhz will give issues 🤣

Does the 2D chip speed impact the Voodoo chips? I have a feeling it does with these cards. Maybe that's why they did this silly overclocking.

swaaye wrote:

Does the 2D chip speed impact the Voodoo chips? I have a feeling it does with these cards. Maybe that's why they did this silly overclocking.

No, 3d part running at 50mhz anyway.
p.s. I edited this inf file in single planar driver(changed 72 to 58) and now there are no any artifacts.

Yeah but the Voodoo hardware interfaces with the 2D chip. Maybe higher 2D clock improves 3D. Voodoo Rush is quirky like that. You could test it.

Better i'll overclock 3d part from 50mhz to 60 mhz. It's sure improves 3d 😀

swaaye wrote:

Yeah but the Voodoo hardware interfaces with the 2D chip. Maybe higher 2D clock improves 3D. Voodoo Rush is quirky like that. You could test it.

Nope, just as any Geforce etc. will not improve the speed of an attached voodoo. 2d part works completely separate and also has it's own memory.

From what I've read on old usenet posts, Rush shares its framebuffer with the 2D chip. This allows it to do 3D in a window.

Rush had a negative rep for lower performance and lower compatibility than Voodoo1. There has to be something that reduces its efficiency and it seems likely to be a relationship between it and that Alliance chip.

I think it only shared the pci interface/bandwidth but i don't know how it can do windowed mode while voodoo graphics can't.

There's a youtube video about the ''3d'' part of the alliance as it also had it's own 3d acceleration (well, something like that). So i always thought about it beeing a voodoo graphics setup on a single card with the passtrough build-in. And because it has to share bandwidth it's slower as 2 loose cards.

But i may be wrong, i don't know the specifics about it.