Installing new AGP card into G4? Help!

[zero]

I installed a new AGP card into a G4 and restarted.
The gray startup screen and apple logo pop up just fine, but after 30 seconds or so, the system kernel panics while still on the gray startup screen.

Is there something I need to do to get the card to work? (It works on another G4 just fine)

TIA!

[Black Landlord]

What are the two G4s?
From Lowendmac:

The video card on G4 systems made after 1999.12.02 is "up to 40% faster" and includes a DVI interface for digital flat panel displays.

Because this model was created before Apple adopted the ADC port (which provides power to an external monitor), the Sawtooth G4 is unable to support ADC displays. It may also be incompatible with AGP 4x and later cards that include a retention tab. Because of voltage differences between the AGP 2x and 4x specs, newer cards may also be electronically incompatible with the Sawtooth G4.

A cuda reset couldn't hurt.

[zero]

After resetting the CUDA, I got to the Login Screen, and then logged in. After a couple of seconds (just before displaying the desktop) the screen changed resolution automatically and all the video signal was lost.

I hit the reset button on the machine, and logged in again. It works!!!

THANKS!