Seasonic is expanding its lineup of fanless power supply units (PSUs), previously available only in 600W models, by offering three wattage options: 700W, 500W, and 450W.

All four fall under Seasonic's Prime Fanless TX family. Somewhat surprisingly, each is either 80 Plus Platinum or Titanium certified. These two certifications are Gold, Silver, Bronze, and the regular 80 Plus (in order of decreasing size).

Velocity Micro, a Boutique Builder, has a pretty good primer on the 80 Plus certification program that is worth a read. In short, these certifications indicate a level of efficiency, which in turn relates to how much (or how little) energy is wasted as heat. [A power supply's job is to convert AC power from an outlet into DC power that can be used by other components. The rated efficiency is the power output to these components divided by the watts drawn from the outlet. This means that a 500W power supply with a rated efficiency of 50% will consume 1000W before reaching peak output. In this example, the remaining 500W is wasted as heat in the conversion process. The efficiency of a power supply also depends on the percentage of rated load being output. Most power supplies are at their maximum efficiency around 50 percent load, or 250 W in this example," explains Velocity Micro, Inc.

Returning to Seasonic's new fanless models, the highest wattage model (700W) is 80 Plus Titanium certified. This means it is at least 94% efficient at 100% load. In contrast, the 80 Plus Bronze certification requires 82 percent efficiency at full load; it is quite impressive that Seasonic models can maintain ultra-high efficiency levels without active cooling.

Fanlesstech noticed these new models added to the Seasonic website. All four PSUs are fully modular: both the 700W and 600W models have a single 24-pin main power connector, two EPS 12V connectors, four 8-pin/6-pin PCIe connectors, ten SATA connectors, five 4-pin peripheral connectors, and one Molex-SATA adapter.

The 500W and 450W models have half the number of 8-pin/6-pin PCIe connectors (i.e., two) and eight SATA connectors instead of ten.

Pricing has not yet been announced. For reference, the 600W model debuted at $190, which is expensive; the 500W and 450W models should be cheaper; all four models come with a 12-year long warranty.