USB 3.0 has raised the limit for the transfer rate, ensuring that external hard drives are as powerful as internal. Capable of supporting a transfer rate of up to 5 Gbps, USB 3.0 can support the fastest hard drives, including solid state drives (SSDs). In addition to the drastic increase in maximum transfer rate, the addition of the five signaling pins in USB 3.0 allows users to use a hard drive with 900 milliamps of power, instead of the 500 milliamps from the old USB 2.0. This allows for the enclosure, equipped with USB 3.0, to support any drive, especially energy efficient SSDs.