OK i don't know if this question has been ask, i search for it but could not find it.

What is the difference between standard ballast and a digital ballast?

I want to install hids on my car but don't know which one to go with, because i heard with the digital ballast it uses less amps on the start up, I don't know if that what the cause of the flickering in the standard ballast's that flicker if you do not connect them to a relay or capacitor to make reach the right amperage.