X-bit labs

ATX Power Supply Units Roundup. Part VII (page 13)

Category: Other

by Oleg Artamonov

[ 09/04/2007 | 10:40 AM ]

Rosewill Turbo Series RT550-135-BK (550W)

Unlike the previous famous brand, Rosewill has never taken part in our tests although offers quite a lot of PSU models. Rosewill doesn’t have its own production facilities, though. For example, the reviewed model is manufactured by the Hong-Kong-headquartered Wintech Electronics (we have reviewed its products before) as is indicated by the UL certificate number on the PSU label.

The PSU has a larger case than standard (with a length of 155mm instead of the standard 140mm) and presents a odd mix of a fashionable 135mm fan with an outdated design without active PFC (the mains voltage switch is a clear indication of that; a PSU with active PFC wouldn’t need one). Today, only low-end PSU models are made without active PFC. As a matter of fact, the RT550-135-BK is the only power supply without PFC in this review.

Internally, it is a typical PSU from Wintech. It is a classic design with a half-bridge inverter, once very popular but now becoming obsolete due to the arrival of more advanced controllers. The assembly is not very neat as you can see by the capacitor in the top right corner. The developer could not fit it into the PCB and the capacitor hovers above the surrounding elements on its legs. The drop of glue it was fixed with on the nearby choke had already cracked when I opened the PSU up and the capacitor was loose.

Note that the PSU has no PFC whatsoever, passive or active. This indicates its targeting at the American market because a PSU can’t sell in Europe without being equipped with at least passive PFC. In the United States the version 4 and higher Energy Star certification can only be obtained with a power factor of 0.9 and higher (such a power factor can only be achieved with active PFC), but this certification is not obligatory.

By the way, Wintech products are easily identifiable, even without the UL certificate number, by the characteristic coloring of the components: yellow capacitors, blue transformers, and orange heatsinks. Compare with this or this power supply for example.

Having a total wattage of 550W, the PSU offers only two “virtual” +12V lines with a combined current of somewhat higher than 30A. This is not much, just a little higher than the requirements of the version 2.2 Power Supply Design Guide to 450W power supplies. For example, the Thermaltake Purepower RX (see below) with a rated wattage of 550W offers a max load of 41A on the +12V rail and the 500W Zalman ZM500-HP provides a load up to 34A.

The PSU offers the following cables and connectors:

• Mainboard cable with a 20+4-pin connector (36cm)
• CPU cable with a 4+4-pin connector (39cm)
• Two graphics card cables with 6-pin connectors (41cm)
• Two cables with four Molex connectors and one FDD mini-plug on each (40+15+15+15+15cm)
• Two cables with two SATA power connectors on each (40+15cm)

The cables are sleeved.

The PSU has a normal selection of connectors but I guess there should be more SATA and PATA power plugs. The cables are somewhat too short. They are 10-15cm longer in most other PSUs.