USB 3 vs USB 2: Buffalo HD-HXU3 hard drive speed tested

In the beginning, a coalition of the finest tech minds brought us the plug-and-play phenomenon that was USB. Then, a coalition of slightly brainier bods upped its game to bring us the miracle that was Hi-Speed USB 2. Today, Crave has the Buffalo HD-HXU3, the very first external hard drive in the UK that uses the SuperSpeed USB 3 standard. SuperSpeed USB 3, people! Pull up a chair and let's take a butchers'.

Before we rip the drive itself to shreds, sniffing at its innards to discover what manner of secrecy it hides, let's talk about the USB 3 standard in general. Its major advantage over USB 2 is its improved speed. USB 2 tops out at a maximum throughput of 480Mbps, but in reality, the actual throughput depends on many external factors. USB 3, in contrast, tops out at 4.8Gbps -- 10 times higher than USB 2, and 1.8Gbps quicker than a SATA hard drive. That's the theory, at least.

In practice, USB 3 -- or at least the Buffalo HD-HXU3 -- isn't anywhere near its promised throughput, but it's still fast. With its accompanying PCI Express interface card connected to our test PC, we fired up the synthetic Atto Disk Benchmark appliation, which measures performance with various transfer sizes and test lengths for reads and writes. Here, we saw peak read rates of 119Mbps and peak write rates of 83Mbps in USB 3 mode. The same benchmark, repeated in USB 2 mode, yielded far slower results. Atto recorded a peak read speed of 29Mbps and peak write of 25Mbps.

In real-world testing, things were a little more impressive. We copied a 13.1GB .mkv 1080p movie file from the Buffalo HD-HXU3 to a Hitachi Ultrastar 15K300 SATA drive with 16MB of RAM and a 15,000rpm spin speed. The entire process took 2 minutes exactly. We repeated the same test with the same disks in USB 2 mode and the test took a whopping 8 minutes 11 seconds.

Are we impressed by USB 3? Well, yes and no. On initial results, the Buffalo HD-HXU3 is around four times faster over USB 3 than it is over USB 2, which is significant, but it's nowhere near as quick as one might expect. Still, it's definitely a step in the right direction and we expect these devices to get even faster over time, as USB chipsets reach full maturity and software is tweaked to optimise performance.

In the meantime, Buffalo plans to release three versions of the product: a 1TB model for £110, a 1.5TB model for £160, and a 2TB model for £240 -- all of which are due at the end of November. The PCI Express interface card, required to enable USB 3 support, will sell for £40. PCs supporting USB 3 as standard should begin appearing towards the end of the 2009.

Disclosure: The disk inside our HD-HXU3 test unit uses a SATA interface limited to 3Gbps, and the PCI Express interface card uses an NEC chipset that may not feature in final retail models.