The Terabyte Battle

Seagate Barracuda 7200.11 - ST31000340AS (1 TB)

The new "Cuda" is available at three capacity points, to fit the requirements of storage-intensive applications in the workstation segment, the high-end desktop and gaming space, as well as for all applications with a high demand for storage capacity. The smallest 7200.11 drive stores 500 GB, the mid-size model holds 750 GB, and the top model accommodates a full terabyte when calculated at 1000 bytes per kilobyte. Per the binary definition, where one kilobyte equals 1,024 bytes, this drive - as well as the other terabyte HDDs - stores only 931 GB. This is the capacity that Windows will display once you format your terabyte drive, so don't be surprised about the difference. Both are accurate numbers; it's just a question of definition.

Compared to the Barracuda 7200.10, with its <200 GB per platter, the eleventh Barracuda generation increases this figure to approximately 250 GB per platter. Therefore, it is obvious that the new Barracuda 7200.11 employs four platters to get its terabyte of storage together. Western Digital goes the same way with its Caviar GP drive, storing one terabyte on four platters. Hitachi is the only hard drive maker to implement a five platter design with its Deskstar 7K1000.

More platters give hard drive makers the option to release higher capacity drives using proven technology, but every additional platter increases drive weight, power consumption, heat dissipation and in theory even the probability of hardware failures due to wear and tear. In practice, however, it is extremely difficult to prove this, as the hard drive makers do not release the necessary details. As recent history tells us, Hitachi's approach of offering a five-platter terabyte drive rather early gave the firm a 6-month head start and the entry in future history books as the hard drive maker that released the first terabyte drive.

The lower platter count also brings business advantages: the drive maker with the highest per-platter capacity will be able to produce budget drives at the lowest cost. 250 GB capacity per platter makes it possible to produce entry-level hard drives at up to 250 GB total capacity, or 500 GB drives with only two platters. Being able to offer high capacities with the smallest number of parts is the key to being competitive from a business standpoint. It's a pity that we haven't seen Samsung's terabyte hard drive yet, which is expected to store the full terabyte on only three platters.

How does the four platter design look in everyday life? Seagate's datasheet claims a sustained data transfer rate of 105 MB/s, which we could almost reach on a system based on Intel's ICH8 Southbridge. On our storage reference system, the hard drive still jumps over the 100 MB/s mark, and hence is the first desktop hard drive to deliver a three-digit transfer rate. At the same time, it also overtakes the 10,000 RPM Western Digital Raptor drives in most of the benchmarks. Its access time of 12.7 ms is still clearly longer than that of the Raptor, but the new Barracuda 7200.11 beats any other 7200 RPM hard drive with the exception of the aged 7K250 Deskstar by Hitachi. Finally there is a NCQ drive with a decent access time, which the I/O benchmark results reflect well.

We measured a maximum surface temperature of 49°C (120°F) after almost two hours of intensive operation. This is a good result for a four platter drive. However, WD's 750 GB drive has an equal geometry and runs slightly cooler. Vibration and noise are within the known boundaries: a Deskstar 7K1000 by Hitachi makes more noise than the 7200.11, while the WD10EACS by Western Digital is the only terabyte drive that actually is quiet.