Thunderbolt is the relatively new connector that combines PCI-Express and DisplayPort. It lets you connect multiple peripheral devices to your computer and has extremely high transfer rates. The 5big Thunderbolt comes with two Thunderbolt connectors. You can use one for connecting the external hard disk to your computer or laptop, and the second one for adding other Thunderbolt devices or even a monitor. You can use pretty much any recent monitor since there are adapters available for Mini DisplayPort to HDMI, DVI or DisplayPort. That means you can also connect a monitor with single cable, and with a laptop you just need the Thunderbolt cable, the screen, and the power supply.
Impressively, LaCie does include a Thunderbolt cable. Quite often you're forced to buy the expensive cable separately. Here you get a black, 50 cm Thunderbolt cable which is a bit short, so might want to buy the 2 meter cable from Apple anyway.
Installing the LaCie external hard disk is simple. Mac OS X immediately recognizes the device, and you can use it right-away. A CD-ROM is also include with software and documentation. The software consists of a basic LaCie RAID monitor which you don't really need for using the LaCie 5big Thunderbolt. Nevertheless, it's a bit odd that LaCie included the software on a disc instead of a USB stick, considering many Apple products don't have a DVD drive.
With the hard disks in RAID 0 the performance is of course very impressive, in BlackMagic Disk Speed Test we got a write speed of more than 570 MB/s and a read speed of 617 MB/s. That's quick, and it's confirmed by AJA System Test with a write speed of 617 MB/s and a read speed of 742 MB/s!
Two disks in RAID 0 achieve a speed of 350 MB/s for reading and writing in BlackMagic. According to AJA it's 342 MB/s for reading and 350 MB/s for writing, and the single disk performance is also very good, with 172.4 MB/s for writing and 172 MB/s for reading. The AJA System Test registered 172.9 MB/s for writing and 165 MB/s for reading.