View Full Version : PSU - what components use 3.3V/5V/12V?

11-21-04, 02:25 PM
I know the CPU and motherboard components use 3.3 from the PSU. A 4-pin molex has 5V and 12V. The 4-pin P4 motherboard connector supplies 12v. But what voltage is actually used by any given component?
hard drive - 5V or 12V?
optical drive - 5V or 12V?
floppy drive - 5V or 12V?
video card - 5V or 12V?

For example, I this will help me know whether my video card gets more juice when I unplug a second hard drive or optical drive, etc.

11-21-04, 11:47 PM
Check out this link...has the info you need, I think: http://www.bleedinedge.com/guides/psu_select/psu_select_06.html

And, while it doesn't break down the individual rails, I find this page useful also: http://www.jscustompcs.com/power_supply/

11-24-04, 11:43 PM
Wow, those chips use up a lot of power!