I'd like to use a 1100W HP PSU from a Z800 workstation to power a test bench I'm building. One problem is that it doesn't have a 3.3V output. Will a standard ATX motherboard freak out without it? Can I use a DC to DC buck converter on the 5V rail and supply the 3.3V that way? I know it's used for current sensing, but I think the HP PSU is using the 5V for that. Any thoughts?