Seagate FreeAgent GoFlex 1.5TB Portable USB 3.0 HDD

Table of Contents

The Seagate FreeAgent GoFlex 1.5TB is the largest portable bus-powered external hard drive money can buy, supports the new USB 3.0 standard and features a unique interchangeable adapter interface.

November 28, 2010 by Lawrence Lee

Seagate FreeAgent GoFlex USB 3.0 1.5TB
Portable External Hard Drive
Street Price

In recent years, the increase in capacity and decrease in price of magnetic storage has made the external hard drive one of the most affordable, useful PC-related accessories. They are available in two basic forms — a) the hefty, high capacity model utilizing a desktop hard drive that requires AC power, and b) the more expensive, 2.5″ drive version with lower capacity that is USB-bus powered. The former is best suited as a backup device, while the latter is handy for carrying large amounts of data on your person.

The anatomy of an external hard drive is dead simple. The drive is secured inside a housing made of metal and/or plastic and its internal interface (typically SATA) is connected to a small controller board that converts it into a more accessible external connection, USB usually but also FireWire and/or eSATA.

The Seagate FreeAgent GoFlex 1.5TB box.

With the advent of USB 3.0, many manufacturers have been content to update the controller in their enclosures and call it a day. Seagate, on the other hand, has taken a new approach with their FreeAgent GoFlex series of portable hard drives. Not only does it support USB 3.0, but our sample’s 1.5TB capacity is groundbreaking for a bus-powered drive. Furthermore, the GoFlex line is described by Seagate as “upgradable”.


So does that mean you can easily swap the hard drive inside? Well no. For starters, the housing of the 1.5 TB model is 22mm thick— like the Seagate FreeAgent Go 1TB we reviewed last summer — and meant to hold only thicker-than-usual 12.5mm drives, which are generally not available as bare drives. Only the standard 7.5mm thick drives are widely available as bare drives, and these are used in the GoFlex models up to 640 GB capacity. Secondly, the drive appears to be attached to the casing firmly, presumably with some type of adhesive. It is not meant to be opened up.

USB 3.0 adapter detached.

By “upgradable”, Seagate is referring here to the GoFlex’s modular adapter, which can physically detach, exposing the power and data connectors of the drive inside. A series of replacement plug-in adapters are sold separately various interface types. You can start with the standard USB 2.0 adapter and move up to USB 3.0 later on when your system supports it rather than buying a new drive. USB 3.0, FireWire, and powered eSATA adapters are available for US$15 to US$25. You can buy the bare drives with just the housing as well, but it appears most retailers prefer stocking ready-to-use versions with an adapter included. The 1.5TB model has no USB 2.0 option, shipping with a USB 3.0 adapter by default.

Seagate FreeAgent GoFlex Series: Key Features
(from the product
web page
Feature & Brief
Our Comment
Features USB 2.0 or 3.0 plug–and–play connectivity Despite its 480mbps rating, USB 2.0 cripples the performance of modern hard drives. USB 3.0 should be much faster.
Includes pre–loaded easy–to–use backup software With many excellent free alternatives, it’s not really necessary.
Lets you upgrade to USB 3.0, FireWire® 800 or eSATA The modular nature of the GoFlex sets it apart from every other external hard drive on the market.
Allows you to access your content on your TV, network and on–the–go when combined with other GoFlex devices Other GoFlex devices can turn a connected GoFlex hard drive into storage for a network media player or into an internet-accessible NAS.


Seagate FreeAgent GoFlex 1.5TB: Specifications
(from the product
web page
Model Number
USB 3.0
120mm (4.71 in)
89mm (3.51 in)
22mm (.87 in)
Weight (typical)
280g (.62 lb)
Shipping Weight
.44kg (0.97 lb)
Encryption 192-bit Triple DES
Automatic Backup Software PC & Mac
Warranty 2 years


The FreeAgent GoFlex 1.5TB measures 120 x 89 x 22 mm (or 4.7 x 3.5 x 0.9 inches) and weighs 0.44 kg (just under 1 lb). The top of the enclosure is composed of smooth glossy plastic while the bottom has a rougher matte surface. Despite its high capacity, which might require more power to spin-up, the included 18 inch USB cable has only one connector, not two, as sometimes supplied to ensure adequate power via the USB.

With USB 3.0 adapter detached, the drive’s SATA interface is revealed. The opening is too cramped for a regular SATA data and power cable.

Connector for the USB 3.0 cable.

Once attached, the modular controller is slightly loose, but difficult to dislodge accidentally. A pair of white LEDs light up when a USB 3.0 connection is established.

The GoFlex’s modular nature also makes the adapter useful in other ways. It can be used with any 2.5″ SATA hard drive without the external housing. But 3.5″ drives require more power to spin up than is provided by USB.


Test Platform:

Testing tools:

File Transfer Suite:

  • Small Files:
    1,250 small HTML, JPEG, and MP3 files totaling 871MB.
  • Large Files: Four large AVI files totaling 4194MB.
  • Huge File: One MKV file, 3799MB in size (not really “huge” but generates similar MB/s results as single 10GB+ sized files)

File Transfer Performance

To gauge the performance of the drive we conducted a series of file transfers from and to a 600GB VelociRaptor, arguably the fastest hard drive currently in production. We tested the drive connected to both USB 3.0 and USB 2.0 ports and compared the results to that of a WD Scorpio Blue 500GB using the same GoFlex adapter and connected to an internal SATA port.

So how fast is USB 3.0? Pretty darn fast compared to its predecessor. The GoFlex copied large files from the VelociRaptor more than 250% quicker when using USB 3.0. The drive inside the enclosure seemed quite speedy as well, beating the 5400RPM Scorpio Blue connected using the GoFlex USB 3.0 adapter and internally via SATA2. Its performance was surprisingly weak when dealing with large batches of small files though, even when both drives were tested using USB 2.0.

Read speeds were much better for all the drives/interfaces tested, and in this regard the GoFlex had no trouble with smaller files. These tests also show the Scorpio Blue on USB 3.0 was basically the same speed as when internally connected. In this scenario there wasn’t much of a USB 3.0 bottleneck.

HD Tune Performance

HD Tune Benchmark: WD Scorpio Blue 500GB (SATA2).

HD Tune Benchmark: WD Scorpio Blue 500GB (USB 3.0 via GoFlex adapter)

Quick scans using HD Tune review hardly any difference between the Scorpio Blue connected via SATA2 and through USB 3.0 using the GoFlex adapter. It’s eerie how the numbers are exactly the same except for a 0.1 ms increase in access time, and a loss of about 20 MB/s in burst speed with USB 3.0.

HD Tune Benchmark: Seagate GoFlex 1.5TB (USB 3.0).

The GoFlex drive on USB 3.0 has better overall read speeds and access times than the Scorpio Blue, even at the inner tracks where performance is typically very slow on large drives.


For a drive of its size, the GoFlex 1.5TB model is extremely quiet, but this was no surprise, given our experience with the previous GoFlex 640GB and 1TB samples. We checked its acoustics at our standard 1m distance, as well as at the ISO 7779 standard seated user distance of 0.6m.

Noise Measurements (SPL)
idle (on foam)
13~14 dBA
12 dBA
idle (on table)
16 dBA
13 dBA
seek (on table)
17~18 dBA
15~16 dBA
Ambient noise level: 11 dBA

The overall noise level was just as low as with the previous GoFlex samples, but the level of vibration was up a notch or two. While the drive inside is well-muffled, its noise level can rise sharply depending on what type of surface the casing is placed on. On a block of foam in our anechoic chamber, the GoFlex measured the same as the previous GoFlex models: 12 dBA@1m and just a little higher from 0.6m. But without that damping foam, the vibration produced by the drive caused noticeable hum on our wooden table, with the amount varying depending on what portion of the table it was placed on. It measured 15 [email protected] at the best spot we could find. Sometimes pressing down on the drive momentarily helped. Seek activity was relatively soft.

It’s quite probable that this 1.5TB model has one more platter than the earlier 1TB model. It’s also possible that our earlier samples were exceptional with regard to vibration. In any case, the vibration-triggered noise is easy enough to avoid. Just placing the GOFlex 1.5TB on any reaosnably soft surface — even a paperback book — keeps it to a minimum. Also, most Windows 7 or Vista PCs in any kind of power saving mode automatically puts the GoFlex to sleep when inactive for a couple of minutes, so even if there is noise, it’s only there while the drive is actively being used.

Seagate GoFlex 1.5TB idling on a wooden surface.

Frequency analysis revealed a fundamental tone at about 90 Hz indicating the drive spins at approximately 5400 RPM.


These recordings were made with a high resolution, lab quality, digital recording
system inside SPCR’s own 11
dBA ambient anechoic chamber
, then converted to LAME 128kbps encoded MP3s.
We’ve listened long and hard to ensure there is no audible degradation from
the original WAV files to these MP3s. They represent a quick snapshot of what
we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — 0.6 meters is a reasonable typical distance between a seated user and an external hard drive. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recordings start with 5 to 10 seconds of ambient noise, then 10 second
segments of the drive at idle and then seeking.


USB 3.0 vs. SATA

The modular adapter of the GoFlex gave us an opportunity to compare USB 3.0 and SATA performance directly using a second drive, the WD Scorpio Blue 500GB. When writing files the speed of both interfaces was almost identical, with SATA2 winning out by a negligible amount (less than 1MB/s). When reading files the difference was greater but marginal except when dealing with small files. For some reason reading small files was about 37% slower. At this time we cannot determine whether the GoFlex adapter or the NEC controller on our Asus motherboard was to blame.

USB 3.0 vs. USB 2.0

While transferring files using USB 3.0 was almost as fast as an internal drive; the improvement over USB 2.0 was staggering. USB 2.0 bottlenecks maximum hard drive throughput down to about 35MB/s. Even using a 5400 RPM notebook drive, you can expect double the speed by using USB 3.0.

Seagate FreeAgent GoFlex 1.5TB

First and foremost, the Seagate FreeAgent GoFlex 1.5TB offers more capacity than any portable (bus powered) external hard drive by 500GB, an impressive feat on its own. While you can get 2TB and even 3TB external drives, they are only available in bulky desktop models requiring AC power.

The USB 3.0 adapter included with the 1.5TB model snaps on securely and can be detached for use with other notebook drives should the need arise, effectively making it two products in one. If you buy a smaller USB 2.0 GoFlex, you can swap it with a USB 3.0 adapter when the time comes, and the old adapter doesn’t become a completely useless dongle. We also like that it can be powered with a single USB port, whether it be 2.0 or 3.0. Furthermore, the drive is fairly quiet, though the vibrations it produces may be problematic depending on what surface you put the drive down on. This is to be expected with a such a high capacity notebook drive inside.

We determined that the drive inside the GoFlex 1.5TB is a 5400 RPM model. Compared to a WD Scorpio Blue 500GB using the same USB 3.0 adapter, the GoFlex’s internal drive is a bit faster except, again, when reading small files. This performance issue extends beyond the interface/controller and seems to affect the drive itself as well, compounding the problem. If the GoFlex has an Achilles’ heel this is it. We also wish you could take the enclosure apart completely, particularly for diagnostic purposes.

The GoFlex 1.5TB typically retails for about US$210 which is very high in terms of capacity:price compared to most 1TB portable external drives. However we remind you that it is the largest USB-powered drive you can buy and the USB 3.0 connectivity, if you can take advantage of it, makes a huge difference. At the time of writing, Newegg is selling it for US$150 as part of their Black Friday sale. At that price we have no qualms whatsoever about recommending it.

Our thanks to Seagate for the FreeAgent GoFlex 1.5TB portable hard drive sample.

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Find the best price for a Seagate FreeAgent GoFlex drive with the SPCR/Pricegrabber Shopping Engine.

SPCR Articles of Related Interest:

Consumer SSD Battle: WD, Kingston, OCZ, Intel
WD Caviar Black 2TB & VelociRaptor 600GB
Samsung EcoGreen F4 &
Seagate Barracuda XT 2TB Hard Drives

Seagate Momentus XT: The Best of Both Worlds?
2TB EcoGreen F3 Hard Drive

Seagate FreeAgent Go 1TB and 640GB portable USB drives

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this article in the SPCR forums.

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