On Figure 18 you can see Galaxy 1000 W label stating all its power specs.

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Figure 18: Power supply label.

What immediately caught our eye were the five separated +12 V lines listed on the label (see Figure 18). As we explained on previous pages, this power supply features two separated +12 V circuits, not five.

As it happens to all high-power units nowadays, Enermax uses a “virtual rail” concept, where they label their power supplies as having separated +12 V rails but inside the unit they are all connected together to a single +12 V rail on the power supply printed circuit board. Unfortunately all manufacturers seem to be doing like this to match the ATX12V 2.x and EPS12V specifications, which require the power supply to have separated +12V rails.

In the case of this power supply from Enermax this problem isn’t so bad as it has, in fact, two independent +12 V rails.

The +12 V wires are separated into five groups, +12V1, +12V2, +12V3, +12V4 and +12V5. +12V1 and +12V2 are connected to the first transformer, i.e. the +12 V “CPU” output, while the other three wire groups are connected to the second transformer, i.e. the +12 V “peripheral” output. The first two groups are really are really connected only to the EPS12V1 and ATX12V/EPS12V2 connectors, so this rail is really the “CPU” rail as Enermax claims.

We can see these connections on the pictures below. On Figures 19 and 20 you can check how +12V1 and +12V2 wires are connected together on the first +12V rail and on Figure 21 you can check how +12V3, +12V4 and +12V5 are connected together to the second +12V rail.

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Figure 19: How +12V1 and +12V2 are connected.

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Figure 20: How +12V1 and +12V2 are connected.

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Figure 21: How +12V3, +12V4 and +12V5 are connected.

From the previous page we came with some maximum theoretical numbers for the +12V CPU output (960 W), +12 V peripheral output (960 W), +5 V (400 W), +3.3 V (264 W), +5VSB (100 W) and –12 V (12 W).

As we mentioned earlier the maximum current/power each line can really deliver will depend on other components, especially the transformer, the coil, the capacitor and the wire gauge used.

The +12 V CPU output of this power supply is labeled as 408 W, well below the 960 W maximum the two rectifiers can handle. The +12 V peripheral output of this power supply is labeled as 492 W, also well below the 960 W maximum its two rectifiers can handle.

Enermax labeled +5 V and +3.3 V outputs as if their circuits were connected together to the same transformer output or to the same rectifiers, i.e. using the “combined power” concept. As we’ve seen on the previous page, this power supply is the first one we’ve seen using completely independent circuits for these two voltage lines, so Enermax could have stated separated wattages for each output on the power supply label. As they stated the maximum current of  30 A for each output, we can easily calculate that +5 V output has a maximum power of 150 W – well below the maximum power its two rectifiers can handle (400 W) – and that +3.3 V output has a maximum power of 99 W – also well below the maximum power its two rectifiers can handle (264 W).

+5VSB output is labeled as having a 30 W maximum power, also well below the maximum power its rectifier can handle (100 W). –12 V output is labeled as having 7.2 W, also well below the maximum power its voltage regulator can handle (12 W).

Funny enough the total labeled power spec of this power supply, 1,000 W, is less than all the labeled individual power for each output added. If we do the math we will find 1,186 W. For this sum we considered 150 W for the +5 V output and 99 W for the +3.3 V output. Enermax has also understated the total power of these two outputs, as together they can deliver 250 W and not 200 W as labeled, because they use two completely independent circuits.

Enermax could simply inflate the labeled power rating of this power supply as the majority of manufacturers do – they could easily label this unit as 1,200 W and people would probably believe.

Unfortunately we don’t have the necessary equipment to make a true power supply review; we would need to create a real 1,000 W load to check if this power supply could deliver its labeled power or not.