Dammit. Something's wrong.
I have to bring this thread up again. I obtained another PowerStorm 300 card, from a completely different seller. But I have the exact same problem with it. It works as a basic framebuffer at 640x480 until I install the drivers in NT4 Alpha. Then after I reboot, no image.
I can't believe that 2 cards from 2 separate vendors have the same problem. Either there's something wrong with the drivers, or the motherboard.
I wish I could find a different set of drivers to try.
(edit) I did find some other drivers labeled as "Powerstorm 300 drivers for Alpha Compaq NT4" but I can't install them. I think they may not be for Alpha but rather x86. There's no easy way to tell which architecture they're meant for just by looking at the driver files that I know of.
It's off to disk I go,
With a bit and a byte
And a read and a write,