ST-550P-AM is a 550 W power supply from Seventeam where you can manually control the fan speed – and can even disable it – a feature called “ASM” by the manufacturer. We’ve already tested another model from Seventeam called ST-550P-AG – which achieved a good performance for an entry-level model – and we were curious to see if ST-550P-AM and ST-550P-AG are the same product (since they have similar model numbers) with only the addition of a fan control knob on ST-550P-AM or if they are completely different units. Let’s see.

One funny detail is the sticker in Engrish saying “Breakage Invalid” instead of “Warranty Void if Broken,” a common “feature” on all Seventeam power supplies.

Seventeam ST-550P-AMFigure 1: Seventeam ST-550P-AM power supply.

Seventeam ST-550P-AMFigure 2: Seventeam ST-550P-AM power supply.

Like ST-550P-AG, ST-550P-AM has active PFC and a 120 mm fan on the bottom, being only 5 ½” (140 mm) deep. With the knob available on the rear of the power supply you can control the fan speed. By pressing it you shut the fan down completely and you have a completely noiseless unit. The power supply still has a thermal sensor attached to the secondary heatsink, so if the temperature there goes too high the fan starts spinning even if you turned it off.

The main motherboard cable uses a 20/24-pin connector and it comes with both EPS12V and ATX12V connectors, sharing, however, the same cable.

Seventeam ST-550P-AM comes with five peripheral cables: one with one 6-pin auxiliary power connector for video cards (ST-550P-AG has two connectors; newer shipments from this power supply are coming with two cables with one six/eight-pin connector each), one (or two on newer shipments) with two SATA power connectors, two with two peripheral power connectors and one with two peripheral power connectors and one floppy disk drive power connector.

Even though all wires are 18 AWG – which is the right gauge for a 550 W product – there are two flaws here. The first one is the presence of only two SATA power connectors. Since nowadays you will have at least two SATA devices – the hard disk drive and the optical drive – you will have trouble installing a second hard disk drive (you will need an adapter). Seventeam fixed this on newer shipments, which are coming with a total of four SATA connectors. Also with the distance between these connectors around only 6" (15 cm) you won’t  be able to connect a SATA hard disk drive and a SATA optical unit to this cable at the same time. ST-550P-AG has this same problem.

The second problem is that this power supply has only one power connector for video cards, while all competing products have two (including ST-550P-AG). Seventeam fixed this on newer shipments, which are coming with two cables.

On the aesthetical side only the main motherboard cable uses a nylon sleeving, which comes from inside the power supply housing.

The distance between the power supply housing and the first connector on each cable is of 17 ¾” (45 cm), and the distance between each connector on cables that have more than one plug is of 5 29/32” (15 cm).

Seventeam ST-550P-AMFigure 3: Cables.

Seventeam is one of the few real power supply manufacturers around. They are the company behind of power supplies from XG/MGE and some models from Cooler Master.

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.