Review – DuoGB FireWire Drive Enclosure

DuoGB FireWire Drive Enclosure
Company: WiebeTech

Price: $179.95 case only; $999.95 case and 500GB using two 250GB 7200RPM drives

James Wiebe’s WiebeTech keeps adding storage products; they’re up to 21 innovative drive products, and climbing. One of the latest additions is the DuoGB drive enclosure, an external FireWire case that holds -two- ATA drives, connected via an Oxford 911 FireWire bridge chip (the best FireWire bridge chip there is). Each drive is physically; sharing only the power supply and FireWire bridge chip. A single bridge chip means that there is only one FireWire cable to connect to the Mac.

MyMac labs got a DuoGB 180 GB loaner for evaluation; let’s review the pros and cons of the unit, and see how it performs. The DuoGB arrived in good shape, surrounded by an almost-excessive number of Styrofoam peanuts. (Note to all shippers; can’t you use bubble wrap?) While the DuoGB is sturdy, you won’t confuse it with the high-style LaCie drive enclosures; the DuoGB is a somewhat thin plain-Jane box. The power button is located on the brushed-aluminum front panel, and the rest of the enclosure is powder-coated steel. You get a FireWire cable, power cord, and a CD with installation instructions that are not really needed by the average Macintosh user. Plug in, tap the power button, and you’re ready to be the digital packrat you always wanted to be!


Having two drives in one case allows for some interesting storage possibilities. As supplied by WiebeTech, the DuoGB mounts two drives on the Mac desktop. Our unit had two 180 GB drives, so we had two separate drive icons.
Having two drives in one case allows the user to enter the world of RAID formatting. We’re not talking bug spray, we’re talking Redundant Array of Inexpensive Drives. While this review can’t go into all the down and dirty RAID tech details (here’s a good FAQ the average Mac user CAN benefit from either RAID level 1 or level 0.

RAID 0 is also referred to as Striping. Data is laid down in stripes across an array of drives for faster I/O performance, but with no data protection.

RAID level 0 on our loaner unit produced a single logical drive (1 icon on the Mac desktop of 345 formatted gigabytes. If one disk is damaged or corrupted, data loss may result (the same as with a single drive installation).
RAID 1 is also known as Mirroring. Identical copies of data on a pair of disks is laid down for total redundancy, but with limited performance and inefficient use of drives. If one disk is damaged or corrupted, the data can be read from the other drive.

Apple now provides both RAID level 0 and level 1 formatting capability in OS X’s Disk Utility software. Prior to OS X, users who wanted to employ RAID arrays had to purchase expensive hardware and software combos. Now, OS X’ers have the software component included in OS X, and it’s brain-dead easy to use; just select the RAID tab, choose the two physical disks, choose Mirror or Stripe, name the set, click Create, and you’re done.

The DuoGB was first tested in the as-shipped configuration of two separate 180 GB disks. without doing any fancy RAID formatting. This is the convenience of the DuoGB; having two external drives without the hassle of two cases, two power cords, and two FireWire cables. The drives popped right up on the desktop with no muss or fuss. The noise level from the internal fan was about average; not silent, but not obtrusive. The DuoGB fan won’t disturb the your iTunes enjoyment.

As plain-vanilla dual drives, DuoGB performance is right in the middle of the pack. Here’s an XBench 1.0 speed test report:

Disk Test 85.25
Sequential 70.82
Uncached Write 70.02 30.55 MB/sec [4K blocks]
Uncached Write 71.33 29.02 MB/sec [256K blocks]
Uncached Read 62.40 9.83 MB/sec [4K blocks]
Uncached Read 82.26 35.49 MB/sec [256K blocks]
Random 107.07
Uncached Write 98.49 1.49 MB/sec [4K blocks]
Uncached Write 126.49 29.02 MB/sec [256K blocks]
Uncached Read 104.62 0.68 MB/sec [4K blocks]
Uncached Read 102.65 20.12 MB/sec [256K blocks]

There’s nothing to report about the user experience in this configuration. You’ve got two external drives, and they’re used in the usual Macintosh way.

The RAID testing was more interesting, as I had no prior experience with either RAID striping or mirroring. Which first; stripe or mirror? The coin toss came up “heads” so I set up the DuoGB as a single striped volume for the first set of RAID tests.

Disk Utility did its RAID stripe formatting quickly and efficiently. I couldn’t help but grin when I saw a single 345-gig volume called “Stripe” (my choice of name) appear on the desktop when the formatting completed. RAID stripers need to remember that a problem with one drive can cause data loss, so back up regularly.

As noted above, the main reason for striping drives is for better performance. XBench’s verdict shows a small speed increase. Repeated tests came up with similar speeds.

Disk Test 88.67
Sequential 71.06
Uncached Write 75.84 33.09 MB/sec [4K blocks]
Uncached Write 72.11 29.34 MB/sec [256K blocks]
Uncached Read 58.08 9.15 MB/sec [4K blocks]
Uncached Read 83.20 35.89 MB/sec [256K blocks]
Random 117.87
Uncached Write 223.40 3.37 MB/sec [4K blocks]
Uncached Write 128.31 29.44 MB/sec [256K blocks]
Uncached Read 112.07 0.73 MB/sec [4K blocks]
Uncached Read 78.48 15.38 MB/sec [256K blocks]

I was a bit surprised there wasn’t more of a speed increase. Benchmarks can be deceiving sometimes, so in desperation, I resorted to a real-world test. I copied a 1.88 folder with 606 items to both a striped RAID volume and to a single drive when non RAIDed.

copy to non-raid volume on DuoGB 2:22 (min/sec)
copy to RAID volume on DuoGB 1:21 (min/sec)

Real-world operation was significantly faster.

RAID level 1, a.k.a. Mirroring, was next on the agenda. Disk Utility created the Mirror array with no trouble. A single 180 GB drive icon appeared on the desktop. Each write to the drive would be mirrored to the second drive; so both drives would have identical data. If problems developed with one physical drive, the second could provide the data. It’s good to note that the RAID tab in Disk Utility provides a “Rebuild” option to try to fix damaged arrays.

What does RAID level 1 Mirroring do for speed?

Disk Test 60.56
Sequential 48.70
Uncached Write 37.65 16.43 MB/sec [4K blocks]
Uncached Write 37.66 15.32 MB/sec [256K blocks]
Uncached Read 59.39 9.35 MB/sec [4K blocks]
Uncached Read 82.04 35.39 MB/sec [256K blocks]
Random 80.08
Uncached Write 96.35 1.45 MB/sec [4K blocks]
Uncached Write 67.15 15.40 MB/sec [256K blocks]
Uncached Read 102.00 0.66 MB/sec [4K blocks]
Uncached Read 67.23 13.18 MB/sec [256K blocks]

Clearly, there are speed tradeoffs for having data redundancy. Having to write data to two disks inflicts a speed penalty. Is it worth it? Many people think so; you’ll have to decide for yourself. I found normal operation slower, but not annoyingly so. I did not deliberately damage the array to test Disk Utility’s ability to repair a damaged array.

One other important fact is that current PowerMac G4’s are NOT able to boot from a RAID array. So, you cannot use the DuoGB as a RAID array with its faster area/write speeds as your boot drive.


WiebeTech offers the DuoGB any configurations ranging from an empty case ($179.95), to being stuffed with two 500 GB 7200 RPM drives ($999.95). The fully-stuffed configuration may be a bit overpriced, as 5 seconds of math shows that Wiebe prices the two 250 GB drives at $410 -per drive-. I found the pricing for the moderate capacity DuoGB’s to be more reasonable.’s dual 180 GB evaluation unit is priced at $639.95, which prices the two 180 GB drives at $230 each. Don’t forget that there is a significant convenience factor is having two drives in one case; one power cord, one FireWire cable, one case, etc. Convenience is worth a certain premium that only you can evaluate.


The DuoGB works as advertised; it can be two separate drives, or it can be RAID level 0 Striped, or RAID level 1 Mirrored. You’re not paying for (or getting) a getting a fancy case, but you do get a reliable mechanism in a very convenient package. Performance is average in both normal and RAID formats. Some configurations are relatively expensive when drive costs are considered.

MacMice Rating: 4 out of 5

David Weeks

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