i've got a dual g4 450, gigabit ethernet agp video, which has always had problems.

now that its being used more for production, once again, its crahing a lot-- kernel panics, finder crashes, etc.
reinstalling os doesn't fix it, remoding peripherals, ram modules, etc....

over time, i have replaced ram, tested the video, etc.
i think its a bad mobo, but I'd like to be sure, before ruling it out as a production computer entirely. I don't think the apple hardware test is available for this computer.

does anyone have any suggestions on testing the hardware to determine once and for all what's at fault?