hello,ask everyone about g4/1g mdd question

recently,someone ask me for change atx power to powermac g4/1g mdd machine,If just match pinout.that's no problem.but everyone knows that atx power no provide 28V.so adc video has problem.I want to know if use adc and d-sub video card(all in one).can I use this one??or just for d-sub???thx