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[nextpage title=”Introduction”]
Barracuda XT is the first SATA-600 hard disk drive to arrive the market. It is also the first 2 TB from Seagate that spins at 7,200 rpm – the other 2 TB drive from Seagate, Barracuda LP, is a “green” model spinning at 5,900 rpm. Let’s see if the new SATA-600 interface will really make a difference.
SATA-600 is the third generation from the Serial ATA interface and as you can assume, it presents a maximum theoretical transfer rate of 600 MB/s. This interface is also called SATA 6 G, standing for 6 Gbps. Since SATA works transferring data serially, its transfer rate must be announced as bps (bits per second), which is the unit used for measuring serial data transfers. But since the beginning of times transfer rates are announced in parallel format – i.e., B/s, bytes per second – 6 Gbps converts to 600 MB/s (and not 750 MB/s, which would be the correct conversion from 6 Gbps to MB/s) because the same channel is used for transferring both data and control information. When we remove the control information from the stream, we end up with 600 MB/s.
You also need to keep in mind that this new speed is the maximum theoretical transfer rate from the interface and not from the hard disk drive, and only measures the maximum speed between the SATA port on the motherboard and the hard disk drive controller that is on the drive. SATA-600 drives, especially the first models like Barracuda XT, won’t even reach near that, just like it happened when the first SATA-300 drives were released.
The new SATA-600 interface is physically identical to SATA-300 and SATA-150, allowing you to install SATA-600 drives on motherboards without this interface. So far there are only two motherboard manufacturers providing products with SATA-600 ports, ASUS and Gigabyte, and only on high-end socket LGA1156 motherboards based on Intel P55 chipset. High-Point also offers add-on cards called Rocket 600 that provide SATA-600 ports on any computer with one x1 PCI Express slot available.
Figure 1: Seagate Barracuda XT 2 TB.
Figure 2: Seagate Barracuda XT 2 TB.
Here is a summary of the hard drives we are going to compare:
| Manufacturer | Model | Model # | Rotational Speed | Buffer | Interface | Market | Price |
| Seagate | Barracuda LP | ST32000542AS | 5,900 rpm | 32 MB | SATA-300 | Green | USD 179.99 |
| Seagate | Barracuda XT | ST32000641AS | 7,200 rpm | 64 MB | SATA-600 | Desktop | USD 299.99 |
| Western Digital | Caviar Green | WD20EADS | 5,400 rpm | 32 MB | SATA-300 | Green | USD 209.99 |
| Western Digital | Caviar Black | WD2001FASS | 7,200 rpm | 64 MB | SATA-300 | Desktop | USD 299.99 |
| Western Digital | RE4 | WD2003FYYS | 7,200 rpm | 64 MB | SATA-300 | Enterprise | USD 299.99 |
Western Digital does not inform at what speed their Caviar Green drives spin; 5,400 rpm is our educated guess.
Prices were reasearched at Newegg.com on the day we published this review, except for Barracuda XT, where the price is the estimated price.
Hard drives typically consume between 8-10 W; “green” models consume practically half of this. The trade-off is obviously performance: since they rotate at lower speeds “green” drives present lower performance. Drives from this category are mainly targeted to external enclosures that are going to be connected to the computer through a USB or FireWire port. Since this kind of port limits the drive performance, the hard disk drive doesn’t need to be the fastest around and thus you can save money both on the cost of the drive and on your electricity bill.
Drives targeted to the enterprise segment (i.e., servers), on the other hand, have a higher reliability, as required for this market segment, with some manufacturers providing extended warranty contracts with the drive. With some enterprise-class drives, for example, the manufacturer can ship a new drive in case of failure before the client sends the defective drive to them, reducing the down time of a server.
2 TB hard disk drives have a real capacity of 1.82 TB or 1,863 GB (3,907,029,168 sectors). As you may be aware, the capacity advertised by hard disk drive manufacturers isn’t the real drive capacity. Read our Hard Disk Drives Capacity Limits tutorial for further information on this subject.
Now let’s compare the performance from these five 2 TB drives.
[nextpage title=”How We Tested”]
During our tests we used the configuration listed below and the only variable component between each benchmarking session was the hard disk drive being tested.
Hardware Configuration (SATA-300)
- CPU: Core 2 Duo E6600
- Motherboard: ASUS P5K-E/WiFi-AP (1013 BIOS)
- Memory: 2 GB Corsair Dominator TWIN2X2048-8500C5D (DDR2-1066/PC2-8500 with 5-5-5-15 timings), configured at 1,066 MHz
- Video Card: Gigabyte GeForce 8800 GTS 320 MB
- Video resolution: 1440×900 75 Hz
- Video Monitor: Samsung Syncmaster 932BW
- Power Supply: Topower PowerBird 900 W
- CPU Cooler: Thermaltake TMG i1
- Optical Drive: LG GSA-H54N
Hardware Configuration (SATA-600)
- CPU: Core i7-870
- Motherboard: ASUS P7P55D Premium (0915 BIOS)
- Memory: Two 1 GB Crucial CT12864BA1339 modules (DDR3-1333/PC3-10600, CL9, 1.5 V), configured at 1,333 MHz
- Video Card: Gigabyte GeForce 8800 GTS 320 MB
- Video resolution: 1440×900 75 Hz
- Video Monitor: Samsung Syncmaster 932BW
- Power Supply: Topower PowerBird 900 W
- CPU Cooler: Intel stock
- Optical Drive: LG GSA-H54N
Software Configuration
- Windows XP Professional using NTFS file system
- Service Pack 3
- Intel Inf driver version: 9.0.0.1008
- NVIDIA video driver version: 175.19
Benchmarking Software
We adopted a 3% error margin. So, performance differences below 3% cannot be considered meaningful. In other words, products where the performance difference is below 3% must be considered as having similar performance.
[nextpage title=”HD Tach”]
Usually we use three programs to evaluate hard disk drive performance, DiskSpeed32, HD Tach and HD Tune. DiskSpeed32, however, would freeze exactly in the middle of the data gathering process and our best guess is that this program isn’t compatible with 2 TB drives. Thus unfortunately we had to keep it out of our benchmarking process.
We tested Barracuda XT 2 TB under four different scenarios. First we plugged it on the same computer we used to test all other hard disk drives, i.e., connected to a SATA-300 port. This is the result marked as “SATA-300.” Here we wanted to know what performance to expect when connecting this drive on a PC without a SATA-600 port. Then we installed it on a SATA-600 port and measured its performance. The hard drive came with firmware version CC11 and Seagate sent us the latest firmware available, CC12. So we repeated these two tests with the newest firmware to see if it would increase performance. It is important to note that we also tested the Barracuda XT drive installed on a SATA-300 port from our new system, however the results were absolutely the same, meaning that other components (CPU, motherboard, etc) don’t make any difference on hard disk drive performance.
HD Tach provides only two results, the burst transfer rate and the average transfer rate. We ran the “long bench” test from this program.
On the burst transfer rate measured by HD Tach Western Digital RE4, Caviar Black and Caviar Green achieved the same performance level, being, on average, 10% faster than Seagate Barracuda XT when this drive was connected to a SATA-300 port. Upgrading the firmware made no difference here, but when connected on a SATA-600 port the burst rate increased 27%, making it to be around 16% faster than the other drives.
Average transfer is certainly the most important parameter for the regular PC user. According to HDTach there is no difference in using a SATA-300 or a SATA-600 port with Barracuda XT, and it achieved the same performance level of its main competitor, Western Digital Caviar Black 2 TB. Its performance was also similar to Western Digital RE4 2 TB. Also upgrading the firmware made no impact in performance here. Seagate Barracuda XT 2 TB was 20% faster than Seagate Barracuda LP 2 TB and 45% faster than Western Digital Caviar Green 2 TB.
[nextpage title=”HD Tach: Read Curves”]
If you are interested, you can find below the read curves plotted by HD Tach for the hard disk drives tested.
Seagate Barracuda XT 2 TB (SATA-300) (CC11)
Seagate Barracuda XT 2 TB (SATA-300) (CC12)
Seagate Barracuda XT (SATA-600) (CC11)
Seagate Barracuda XT (SATA-600) (CC12)
Seagate Barracuda LP 2 TB
Western Digital Caviar Green 2 TB
Western Digital Caviar Black 2 TB
Western Digital RE4 2 TB
[nextpage title=”HD Tune”]
Now we have the results provided by HD Tune.
The burst transfer rate from Barracuda XT 2 TB when connected to a SATA-300 port was on the same level as the one achieved by Western Digital Caviar Black 2 TB and Western Digital RE4 2 TB. Seagate Barracuda LP 2 TB, however, achieved a burst rat
e 12% higher than Barracuda XT 2 TB under this scenario.
When we connected Barracuda XT 2 TB to a SATA-600 port its burst rate increased 12%, being identical to the burst rate achieved by Seagate Barracuda LP 2 TB. As you can see the firmware upgrade made no impact on performance.
According to HD Tune the average transfer rate from Seagate Barracuda XT 2 TB didn’t change with the new firmware version or with the kind of SATA port we used (SATA-300 or SATA-600) and was on the same level of Western Digital Caviar Black 2 TB and Western Digital RE4 2 TB, being 20% faster than Seagate Barracuda LP 2 TB and 44% faster than Western Digital Caviar Green 2 TB.
The maximum transfer rate is achieved when the hard drive is reading data from its outer-most tracks. According to HD Tune the maximum transfer rate from Seagate Barracuda XT 2 TB didn’t change with the new firmware version or with the kind of SATA port we used (SATA-300 or SATA-600).
Here once again Seagate Barracuda XT 2 TB achieved the same performance level as Western Digital Caviar Black and Western Digital RE4.
The minimum transfer rate is achieved when the hard drive is reading data from its inner-most tracks. On this test we saw a performance increase of 16% when running under SATA-600 after we upgraded the firmware.
Here Seagate Barracuda XT 2 TB achieved a performance similar to Western Digital RE4 2 TB, being 4% faster than Western Digital Caviar Black 2 TB.
[nextpage title=”HD Tune: Read Curves”]
If you are interested, you can find below the read curves plotted by HD Tune for the hard disk drives tested.
Seagate Barracuda XT (SATA-300) (CC11)
Seagate Barracuda XT (SATA-300) (CC12)
Seagate Barracuda XT (SATA-600) (CC11)
Seagate Barracuda XT (SATA-600) (CC12)
Seagate Barracuda LP 2 TB
Western Digital Caviar Green 2 TB
Western Digital Caviar Black 2 TB
Western Digital RE4 2 TB
[nextpage title=”Access Time”]
Access time is another important measurement. It measures the time the hard disk drive delays to start delivering data after the computer has asked a given data. It is measured in the order of milliseconds (ms, which is equal to 0.001 s) and the lower this value, the better.
The results presented by the two programs were slightly different, so this time we plotted a chart showing the two programs.
Western Digital RE4 and Caviar Black achieved exactly the same access time, which was 29% better than the access time achieved by Seagate Barracuda XT.
[nextpage title=”Conclusions”]
We were expecting Seagate Barracuda XT 2 TB to smash its main competitor, Western Digital Caviar Black 2 TB, because of the use of the new SATA-600 interface, but this didn’t happen: both achieved the same performance level. In fact, Western Digital Caviar Black 2 TB achieved a somewhat lower access time; so if you are looking for a fast 2 TB hard drive, Western Digital Caviar Black 2 TB has a little bit of an advantage.
It is very important to have in mind that when a new interface is released this kind of result is not unusual, especially with the very first product. As we have explained in the introduction, the new interface expands the maximum transfer rate the interface can handle, but that doesn’t mean that the hard disk drive itself is faster. It should take a while for us to see drives that can benefit from this new interface. In fact probably SSDs will have greater benefit, as many of them are reaching more than 200 MB/s today, so they may reach the 300 MB/s limit way sooner than hard disk drives.