Reducing Power Consumption in a PC

[SpookyElectric]

I can't seem to find any power supplies that are certified to work at 400 Hz (on aircraft) that are larger than 300 Watts. I'm building systems that may exceed this. What are the power hogs in a computer system, so that I can maybe scale them back to reduce power consumption?
Thank you.
In particular does using a video card with passive cooling use a lot less power than one with a fan?

 

[VisiGoth]

There should be many options for 3 phase 400 Hz aircraft use for 7 amp service. As for the computer, there are PC104 form factor vendors of units with standard DZUS spacing with very low powers. I thought 28 V was more of a standard offering. The fanless designs refer to no fan on the processor, not in the unit. There is one I have used that is actually a video chip designed for the set top box industry that happens to have an AMD penti*m on chip. It worked out that the video support was the bulk of the processing wok that had to be done anyway. You power hogs will probably be your ARINC I/O board and video board. Most have a separate video board matched to the LCD display. You can get LED lighting (another power hog) but you will probably opt for the standard cold cathode. By selecting a lower clock rate main board the power can be quite low and you can eliminate the penti*m fan.