TechPowerUp posted a review on the FSP Twins 500 W Redundant PSU
A quote from the article:
The FSP Twins 500 W is a digital redundant server-type PSU that can be housed inside a normal ATX chassis. It offers the hot-swap and redundancy features, but comes at a very high price, and with increased output noise.FSP Twins 500 W Redundant PSU @ techPowerUp