There is an old thread here where I noticed it in testing, both Powercolor V4's run at 3.3 volts, not 1.5 as do the regular 3dfx Voodoo 4.

There are several Cards with 4x AGP connectors that (due to various reasons) are electrically 2x AGP cards.

It's virtually the same with the Kyro2, for example.

These 3.3V Cards will run for a limited (highly variable) time in 1.5V AGP Boards, either until the Video card and/or the Motherboard is destroyed. This can be hours, days, in rare cases even a few months.

For that sole reason many Motherboard manufacturers began integrating protective circuitry into the Boards back in those days, that prevent such combinations from powering up and some give a corresponding warning (usually by a small LED mounted close to the AGP Port).

Therefor, quick "tests" (card POSTs and runs apparently normal) do not qualify as "4x AGP passed".

An indicator of the severe electrical anomaly inflicted on the Card and the Board can be very high temperatures found near the Card's AGP connector after a short period of operation.

maybe some curious addition: installed UT and started with Glide...Is running the start demo fine without freeze , but freezes when entering the menu. driver problem? which one is 100% stable for Ek4 and XP so i can exclude that or find the final solution

i just need glide running stable  8)

forget this post: its freezing too but is there a 100% stable driver? or a special one for the ek4?

i placed a new heatsink on the card and a 8cm fan is blowing on it. but at the backside of the vsa100 it gets too hot to hold your finger for just than one second...i measured the voltage regulator and one of his legs has 2.8V. the vcore for vsa100?

its stable a bit longer now to me...

great solution  ???

it´s now really out of the pc and my old v3 is doing her job again.

finally i tried running it with two 6cm fans@12V blowing on it. the heatsink was around 24°C and it still freezes but after a longer time (2min). any tip for this? maybe a bad voltage regulation?

You cannot modify (as far as I know) the Card to actually run at 1.5V (as opposed to the Kyro2, where a mechanical workaround existed) due to hardware limitations.

Further increasing the Voltage (I assume you mean the AGP Voltage, Vio is usually the CPU I/O Voltage unrelated to AGP) will just increase the risk of damage.

Bottom line :
Either you change the Motherboard or the Card, or you risk destroying any of them... anytime. No known workaround exists, otherwise alot of people would have kept their Voodoo AGP Cards in 4x/8x AGP Systems.

The 3.3V AGP limitation was a hughe deal when the first Pentium 4 Motherboards arrived and 3dfx owners were searching for a solution.

Only the 3dfx Voodoo4 AGP owners were lucky, the only 4x AGP 3dfx Retail Card that ever existed.

Yeah, but AGP 4x only affects card speed...

...not voltages!