Power Distribution
Contents
In Figure 17, you can see the power supply label containing all the power specs.
Figure 17: Power supply label.
As you can see this power supply has two virtual +12 V rails, +12V1 and +12V2 and inside the power supply we could clearly see that each rail is separately connected to the monitoring integrated circuit, which is in charge of the over current protection (OCP). During our tests, however, we couldn’t make this circuit to shut down the power supply, as we will talk about later.
On this power supply each virtual rail is connected like the following:
- +12V1: Main motherboard cable, modular cabling system.
- +12V2: ATX12V/EPS12V connectors.
This is the traditional distribution for power supplies with two virtual rails. We, however, don’t think this is the best distribution for a system with two video cards, because the cards are connected to the same rail and if you use high-end models they can make the power supply to shut down (by activating the power supply’s over current protection) even if they are running inside their specs.
The modular cabling system is connected to the main printed circuit board using two 18 AWG wires for the +3.3 V line, four 18 AWG wires for the +5 V line, two 12 AWG wires for the +12 V line and three 12 AWG wires for the ground signal. These 12 AWG wires are really thick, which is great.
Figure 18: Wires used to connect the modular cabling system to the main printed circuit board.
Now let’s see if this power supply can really deliver 500 W of power.
