
Those who work with digital media require the ability to store and move around colossal amounts of data. It sounds unbelievable, but for every minute of a finished documentary, it isn't unreasonable to have a full hour of source material to edit from. It's no surprise that external storage is simply a part of life for many professionals.
Unfortunately, external hard drives are pretty much always slower than their internal counterparts. To stay mobile, external storage usually utilizes USB or Firewire connectivity, and in both cases this means an instant limitation on how fast data can be transferred: peak transfer rates are only about 400 to 480 Mbit/s. Compare this to the newest SATA standard, which can handle theoretical bandwidth of 3 Gbit/s!
In addition to high performance, one of the major advantages of the SATA interface is its hot-swapping capability, and that makes it a very attractive interface for external storage. Today we will be looking at one of the pioneers of external SATA (eSATA) hard drives: the Seagate eSATA 500 GB.

The Seagate eSATA drive's appearance
The official name of Seagate's drive is ST3500601XS-RK, which is a little bit cryptic, though no more so than any of Seagate's other offerings. Essentially, the unit is an attractive case that contains a Seagate Barracuda ST3500641 7,200 RPM hard disk, a 7200.9 series drive with 500 GB of storage and 16 MB cache. Attached to the case is a SATA cable for connectivity, and an AC adapter cable for power. It is worth mentioning that while we tested the 500 GB drive, Seagate also manufactures a 300 GB version of the eSATA external drive.
The eSATA's design appears similar to the other external solutions from Seagate. The unit's appearance is stylish, brushed silver in appearance with black accents. The power button illuminates a nice blue when powered up, a color scheme that happens to go very nicely with my PC case, though your mileage may vary. The drive is also designed to stack with other Seagate external drives, which is nice. Putting two of these units together in a RAID configuration might be an attractive option for some users.

The box included Promise's eSATA300 TX2 card for PCI.
The unit includes the Promise eSATA300 TX2, an eSATA card that offers two external ports for eSATA devices. This is pretty handy when you consider that only new motherboards have integrated eSATA ports. More on this later.
In addition to the drive and eSATA card, the package contains BounceBack Express V 7.0 software. It's easy enough to use and enables the requisite backup tasks, like backing up entire disks and folders. In addition, Bounceback offers options to schedule backup sets.

The functional difference between Seagate's eSATA and the company's older external drives is that the new model lacks Firewire and USB connectivity. It is this lack of Firewire and USB options that we might change if we had the chance.
To be sure, this drive's strength is its exceptionally fast performance. But external drives typically have another strength that makes them valuable: portability. To migrate Seagate's external drive to another PC easily, that PC must have an eSATA connection (which does NOT mean a regular SATA connector).
Frankly, motherboards that come with an external SATA connection are still fairly rare. This leaves the user who lacks an external SATA connector with two options: either migrate the included eSATA card along with the drive, or open the PC case and plug the drive into a free eSATA connector if one is available. Both of these options require opening up the PC and fiddling with it, which kind of negates the value of having a mobile external drive in the first place.
Of course, you could argue that a media professional is probably going to have these bases covered and will have the newest PC equipment at their disposal, but that's a bit of a rationalization. The long and short of it is that if the drive has to be moved to another PC, there's probably going to have to be some prior planning to get it to work, whereas USB and Firewire drives can travel between PCs very easily.
| System Hardware | |
|---|---|
| Processor(s) | 2x Intel Xeon Processor (Nocona core)
3.6 GHz, FSB 800, 1 MB L2 Cache |
| Platform | Asus NCL-DS (Socket 604)
Intel E7520 Chipset, BIOS 1005 |
| RAM | Corsair CM72DD512AR-400 (DDR2-400 ECC, reg.)
2x 512 MB, CL3-3-3-10 Timings |
| System Hard Drive | Western Digital Caviar WD1200JB
120 GB, 7,200 RPM, 8 MB Cache, UltraATA/100 |
| Test Hard Drive I | Western Digital WD1500AD Raptor
150 GB, 10,000 RPM, 16 MB Cache, SATA/150 |
| Mass Storage Controller(s) | Intel 82801EB UltraATA/100 Controller (ICH5)
Silicon Image SATALink SiL3512 Driver 1.2.0.57 Promise FastTrak TX4310 Driver 2.06.1.310 Promise SATA 300TX4 Driver 1.0.0.33 |
| Networking | Broadcom BCM5721 On-Board Gigabit Ethernet NIC |
| Graphics Card | On-Board Graphics
ATI RageXL, 8 MB |
| System Hardware | |
| Performance Measurement | c’t h2benchw 3.6 |
| PCMark05 V1.01 | |
| System Software & Drivers | |
| OS | Microsoft Windows Server 2003 Enterprise Edition, Service Pack 1 |
| Platform Driver | Intel Chipset Installation Utility 7.0.0.1025 |
| Graphics Driver | Default Windows Graphics Driver |
Let’s examine the performance Seagate’s new eSATA drive and see if it’s as fast as it’s purported to be. First, let’s have a look at read access times.
Benchmark Results
Access Time
The red bar represents the new eSATA external drive attached to the Promise eSATA300 TX2 card included with the drive. For reference, we highlighted in blue the results obtained with a Seagate 500 GB SATA drive, which is what the eSATA external drive contains, only attached internally via the motherboard’s SATA connector.
The result is a bit strange : we recorded a pretty large difference between the eSATA and its internal counterpart. In these access time tests, the eSATA was slowest of the group, even bested by USB and Firewire drives.
In theory, the eSATA should perform identically to the internal SATA drive if it were plugged in to one of the motherboard’s internal SATA connectors, or an external SATA connector if it comes so equipped. Since the actual hard disks are identical, the difference we see between the two is probably a result of latency added with the Promise eSATA300 TX2 card, as opposed to the motherboard’s onboard SATA controller.
Odd results indeed for what we expect to be a very high performance solution. Keep in mind, however, this test is for access time only. The really interesting numbers should appear in the read and write transfer tests.

Once we start measuring data transfer, we see a completely different story, with outstanding performance from Seagate's eSATA external drive. Out of the 36 drives we have tested, the eSATA scored in the top three, performing identically to its internal cousin. Very impressive. Let's see if this performance continues with write transfers.
Write Transfer Rate

Different test, but the same story: the Seagate's eSATA once again scores exceptionally well, identical to its internal cousin and once again in the top three. Clearly, the eSATA is a very fast drive, and an excellent choice for an external solution.

The slow access times seem even stranger in light of the very high read/write transfer performance, but transfer rates are what's important in a drive like this. We wonder if perhaps a driver update might speed up the Promise eSATA300 TX2 card's access times with the eSATA drive. That's speculation, but what we are certain of is that Seagate's eSATA performs where it counts: quickly moving huge amounts of data to and from its platters.
The only other area of note would be the eSATA's inability to easily interface with multiple PCs, as mentioned above. This problem doesn't really lie with the eSATA drive itself, but the lack of external SATA ports on most available motherboards. Still, it would have been nice if Seagate had addressed this with a USB or Firewire port as a backup option.
But these issues are relatively minor. External SATA is a great idea, and we applaud Seagate's entry into this relatively new market. The ST3500601XS-RK is a solid product and we can recommend it highly to those who need fast, mobile data transfer.
Editor's Opinion
While the read access time is troubling, I don't believe the drive is responsible. It's likely a latency issue with the included eSATA card, and I don't think it would impact real world performance when you consider this drive's target market. In all likelihood, no one is going to run any software from these drives - read/write performance is what matters, and for that task, Seagate's eSATA has nothing to apologize for.