Power supplies are arguably the component in a computer that is under the most stress, and one of the most likely to fail. For that reason, big servers have redundant power supplies that can be swapped out while the machine is running. Historically, these redundant PSUs have been proprietary affairs that required custom chassis and mountings. FSP Group's new Twins series redundant power supplies takes a different route, cramming a pair of hot-swappable modules into an ATX-sized shell.
Don't let the small size fool you: each of these little guys is 80 Plus Gold-certified. That means the PSUs have at least 90% efficiency across their output range. FSP currently offers a 500W unit, and has plans to offer a 700W model soon. Regardless of which one they grab, builders will get two 4+4-pin CPU power connectors, two 8-pin PCIe power connectors, six SATA power connectors, and two ol' Molex peripheral connectors. Oh, and a floppy-drive plug.
On a regular desktop machine, it may not be obvious that one PSU module has failed. For monitoring purposes, FSP offers its Guardian monitoring and control software. This functionality requires a connection between the power supply and one of the motherboard's USB headers, but you probably have one free anyway. The software can monitor the DC power output of the Twins, as well as temperature, fan speed, and AC power input quality.
All that fancy functionality doesn't come for free. FSP says the Twins series power supplies should already be available in 500W version for $399. The 700W version will come in at $499.