The new Signature Series from Antec is a premium power supply line, which means that products from this series (so far 650 W and 850 W models were launched) have tighter specs. For example, voltage regulation is set at 3% instead of 5% (7% instead of 10% for the -12 V output). Between the lines the manufacturer says this line has a very high efficiency, although on the specs table they list efficiency as “80% minimum.” Signature 650, also known as SG-650, features a half modular cabling system and only one 80 mm fan, which the manufacturer says is quieter than other 80 mm solutions. Let’s see what is really inside this power supply and why it is so much more expensive than other units.

Of course this power supply features active PFC, what enables Antec to sell this product in Europe. Because of that it also has auto voltage selection.

Signature 650 comes in a fancy hard box, as you can see in Figure 1.

Antec Signature 650Figure 1: Antec Signature 650 box.

Antec Signature 650Figure 2: Antec Signature 650.

This power supply is a bigger than other products on the same power range, being 7 3/32” (180 mm) deep instead of 6 19/64” (160 mm) or even 5 ½” (140 mm).

As mentioned, this product has only one 80 mm fan on its rear side, just like older power supplies. We like better when power supplies have a 120 mm or bigger fan on its bottom as bigger fans provide higher airflow (meaning lower temperature) and lower noise level (as they can rotate at lower speeds to achieve the same airflow level of smaller fans). Antec, however, says that the fan used is quieter than normal, as it uses a PWM (Pulse Width Modulation) circuit to control it. In fact this proved to be true. During our reviews we could only hear the fan working when the power supply was delivering its full labeled power or more. The power supply worked very cool as well (only up to 5° C above room temperature), as we will show you in more details later.

But what is somewhat strange about this power supply is the fact that it uses a “half” modular cabling system, to be used only if you need more cables. Signature 650 comes with the main motherboard cable, ATX12V cable, EPS12V cable, SATA power cable (with three connectors), peripheral power cable (with three standard connectors and one floppy disk drive power connector) and video card cable (6/8-pin connector) coming from inside the power supply. Then it has three connectors on its modular cabling system if you need more peripheral, SATA or video card power cables.

It comes with two SATA power cables (three SATA power plugs each), two peripheral power cables (three standard peripheral power plugs each) and one video card power cable (one 6-pin plug). If you pay attention, the power supply comes with five extra cables, but its modular cabling system has only three connectors, so you can only use three of them at the same time (one of the connectors is reserved for the additional video card power connector).

Antec Signature 650Figure 3: Antec Signature 650.

Antec Signature 650Figure 4: Cables for the modular system.

All wires are 18 AWG, which is adequate for a power supply on this power range.

On the aesthetical side all cables use a nylon sleeving, but they don’t come from inside the power supply, so the wires are exposed on the hole on the front side of the power supply.

This power supply is manufactured by Delta Electronics.

Now let’s take an in-depth look inside this power supply.

Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.