Standing vertically at about 6.25 inches high and about 1.7 inches wide (the base is a stabilizing 2.3 inches wide) the matte silver Extreme is undeniably attractive. The front panel sports only a large but subdued blue power switch/activity light; however, the d2 Extreme's versatility is evidenced by a heavily populated back panel, with two FireWire 800 ports, a single FireWire 400 port, one USB 2.0 port, a Kensington lock port, an AC jack, and a heat-dissipating vent.
As you can gather from the port list, FireWire 800, a.k.a. IEEE 1394b or FireWire B, and its IEEE 1394a predecessor aren't physically compatible in their pure forms, though the new spec does provide for "bilingual" type connections, which the LaCie drive doesn't implement. The higher 100MB per second bandwidth of 1394b comes with the help of two additional wires to assure signal integrity, plus an extra wire for future expansion, hence, FireWire 800 cables and connectors use 9 pins instead of IEEE 1394a's 6 (or 4 without the two wires that provide bus power). But it's also backward-compatible, so you can use 9-pin to 6-pin and 9-pin to 4-pin adapters that ignore the extra wires, though you'll be operating in 1394a mode. Unfortunately, motherboards and PCs that support FireWire 800 are as rare as hen's teeth these days, so, unless you're buying a newer Mac, you'll probably need an adapter such as the Adaptec FireConnect 8300 we used for our testing.
The d2 Extreme's performance in our 400MB folder and 1.9GB large-file copy tests was exceptional. It averaged 10.2MB per second with USB 2.0, 11.4MB per second with IEEE 1394a, and a whopping 12MB per second with FireWire 800. Our previous high-water mark with any interface was 9MB per second. Most of the gain came in 400MB folder tests; reading and writing the 1.9GB file was no faster than what we've seen from other recent external hard drives.
Unfortunately, it's difficult to pinpoint just what contributed the most to the overall performance gain: a fast, recent-model hard drive, the newer-model USB/FireWire bridge chips in the drive and the controller, or a combination of both. From our recent experiences with late-model internal hard drives, we suspect the larger part of the accolades should go to the chips. However, what is obvious is that FireWire 800 offers better performance than USB 2.0 or IEEE 1394a. In a single drive setup like the one we tested, it's a noticeable if minimal gain. However, in a RAID array, the doubled bandwidth and the higher burst transfer rate (61MB per second) should have a much larger impact.
LaCie provides a one-year warranty on the d2 Extreme, though tech support is a toll call and is available weekdays only from 7 a.m. to 5 p.m. PT. However, this external hard drive is easy to use, so the company's printed documentation, support CD, and online support should suffice for most users.