Sony will launch an external Blu-ray Disc rewritable drive this month that can burn BD-R discs that support 6X speed, but users hoping for fast transfers might encounter a bottleneck in the form of their computer.
The 6X speed offered by the BDX-S500U when writing to single-sided discs translates into a write speed of 27MBps, according to the Blu-ray Disc specification. The drive connects to computers via USB 2.0, which has a theoretical maximum speed of 60MBps, but has been measured to run much slower in real-world tests.
Some of that speed is taken away by networking overheads built into the protocol, and more by inefficiences in many USB interface chips. A test earlier this year by Techworld found a USB 3.0 chipset, one of the first to support a new breed of faster USB connections, supported a maximum USB 2.0 write speed of just 11MBps. The speed is also shared among other peripherals on the USB bus, so could fall further.
Sony is bundling a 25GB single-sided 6X BD-R disc and CyberLink Media Suite 8 disc burning software with the drive, but the drive can also write to dual-layer 4X BD-R discs that hold 50GBs of data. It can also record to most of the common DVD and CD rewritable and writable formats.