External Seagate Drives: A Portable 2.5" and a Pocket Drive

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We subjected both drives to a couple of informal, real-world tests to see how they fared in real life. Two tests were chosen: A simple file copy operation, using the BounceBack software included with the Portable 2.5" drive, and a media playback test to ensure that the drives could keep up with a fairly regular data flow.

For the file copy, we backed up the boot partition of one of our main systems onto the freshly formatted portable drives. The partition contained roughly 3.2 GB of data in 20,000 files. The log function in BounceBack reported both the total copy time and the average data rate.

A dramatic difference.

A quick look at the results shows the difference between the drives in a very exaggerated way. Yes, those numbers are correct, the Pocket Drive took almost thirty times as long to complete the backup. Two internal drives in the system (a 160 GB Samsung Spinpoint P80 and a 120 GB Western Digital Caviar SE) performed within 10% of the Portable 2.5" drive — not enough to make a subjective difference.

These results were confirmed by our subjective impressions of the drives. The Portable 2.5" drive felt just as fast as the internal HDDs in the test systems, while the Pocket Drive seemed slightly slower than the flash memory drives that we use around the lab.

Although the Pocket Drive was noticeably slower than any other drives we've worked with, it did not feel thirty times slower by any means. Indeed, later testing showed that, under the right circumstances, it was capable of transferring four gigabytes of data in under 20 minutes. The key to its poor showing was its seek times. While its sequential transfer times were acceptable, the drive slowed noticeably whenever a new file was started, presumably because the drive had to seek to and from the master file table (an index that the drive uses to locate each file) between each file. Multiply that by 20,000 files, and the poor performance begins to make sense.

The second portion of the testing was a usage test to see if the drives were capable of serving as playback media for digital video files. A wide variety of formats, codecs and bitrates were tested:

  • AVI
  • MKV
  • XviD
  • WM9
  • x264
  • DVD (MPEG2 / ~5 Mbps)

No HD footage was tested because no systems were on hand that could reliably play our samples. The most challenging sample was probably the DVD footage, which had a significantly higher bitrate than the other samples, although it was not especially high compared to most DVDs. However, a full length DVD that used the full 9.9 Mbps bandwidth of the DVD format would have been too large to fit on the Pocket Drive. It is the capacity that limits the usefulness of the Pocket Drive for high-bandwidth video, not performance.

Neither drive had any problems keeping up; no dropped frames or audio glitches were ever noticed. The Pocket Drive managed to keep up, even during DVD playback. However, given the Pocket Drive's poor seek performance, it is possible that problems would have developed if the files on the drive had been fragmented. The 19 MB/minute speed that was seen during the first test translates into a bitrate of just 2.53 Mbps — enough for highly compressed footage, but inadequate for all but the lowest quality DVD footage.


Both of the drives were very quiet — hardly a surprise considering the small drives that were used. The Portable 2.5" drive sounded much as you would expect: Like a 2.5" drive. In fact, it sounded just like the 160GB Seagate Momentus 5400.3 that we reviewed not long ago. The external enclosure did very little to reduce the noise from the internal drive, so portable drive sounded much like the bare 5400.3. At idle, a slight hiss could be heard, and seek noise sounded like distant raindrops.

Despite the similarities, there was a significant difference in the amount of perceived noise between the Portable drive and the Momentus. In practice, notebook drives tend to be almost inaudible when installed in a case, but the Portable drive was quite clearly audible because it rested on the desk beside us. Even so, it was still pretty darn quiet. Seeks were only audible when listened for, and the noise would disappear altogether when there was any noise in the background.

The Pocket Drive is the first physically spinning drive we have ever not heard. The drive produced no audible noise, even under heavy load. Only the glowing blue LED told us that the drive was active at all. Holding the drive directly against our ears, we were finally able to hear a faint ticking that was the drive seeking, but even that noise disappeared beyond a couple of inches. Idle noise was never audible. Given that nobody in their right mind will ever use the drive while it is pressed up against their ear, the Pocket Drive is, for all intents and purposes, completely silent.


For mainstream users, the Portable 2.5" drive has all of the winning features for a portable hard drive. It's reasonably spacious, it doesn't require an external power source, it will fit in a jacket pocket, and it's quiet. Its US$300 price tag is a little on the steep side — no doubt the smaller capacities are more reasonably priced — but its advantages far outweigh its drawbacks.

In terms of performance, it had no problems keeping pace with the (admittedly a bit dated) hard drives in our test system and didn't lose much in file transfer times. Subjectively, there was very little difference between the 3.5" PATA drives suspended in the system, and the Portable 2.5" drive connected through the USB 2.0 port.

The Pocket Drive is a tougher sell. Yes, it is silent, but so are flash-based products that can arguably outperform it. 6 GB is not much for an external drive, especially considering that DVD-Rs hold nearly 5GB, and CF media is just becoming available in 8 GB capacities.

Its advantages are its quirks: Hardware encryption, write protect, and a USB 2.0 interface. High capacity flash media that is compatible with USB 2.0 is still scarce, which gives the Pocket Drive a property that flash memory can't match: It's both portable and bootable. Linux-based "Live" installations are increasingly being used for emergency troubleshooting and diagnosis, and the Pocket Drive fits this application perfectly. Its niche may disappear entirely as higher capacity flash media takes off, but for now the Pocket Drive is still a good choice for an emergency boot disc.

Many thanks to Seagate for the USB 2.0 Portable Hard Drive and Pocket Hard Drive samples.


SPCR Articles of Related Interest:
SPCR's Recommended Hard Drives
Seagate Momentus 5400.3: 160 GB Notebook Drive & Introduction to Perpendicular Recording
Enermax Laureate EB205U external notebook HDD enclosure

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