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Hitachi's Deskstar T7K250 hard drive

300MB/s or bust
— 12:00 AM on May 25, 2005

ManufacturerHitachi Global Storage Technologies
ModelDeskstar T7K250
Price (250GB)

HITACHI GLOBAL STORAGE TECHNOLOGIES was the first manufacturer to announce hard drives supporting the new 300MB/s Serial ATA interface, but there's more to Hitachi's new Deskstar T7K250 drives than a faster interface speed. For starters, the latest Deskstar rolls with 125GB platters that are more than 50% denser than the company's older 80GB platters. This drive is also the first from Hitachi to support Native Command Queuing.

We've rounded up a collection of drives from Maxtor, Seagate, and Western Digital to find out how the T7K250 stacks up against the competition. We've also tested the new Deskstar's 300MB/s transfer rates to see where—or whether—they may have an impact on performance.

Drive specs
The snappily-named Deskstar T7K250 succeeds the 7K250 and offers far more than simply an interface speed boost over its predecessor. In fact, the drives are different enough to make us wonder why HGST isn't differentiating the T7K250 from the 7K250 with more than just a "T". Have a look at the differences in specs.

  Deskstar T7K250 Deskstar 7K250
Maximum external transfer rate300MB/s150MB/s
Internal transfer rate105.4MB/s94.6MB/s
Sustained transfer rate32.9-67.8MB/s29.7-61.4MB/s
Average read seek time8.5ms8.5ms
Average typical seek time8.5ms8.8ms
Average rotational latency4.17ms4.17ms
Spindle speed7,200RPM
Cache size8MB
Platter size125GB80GB
Available capacities160, 250GB80, 120, 160, 250GB
Idle acoustics2.8 bels2.6-3.0 bels
Idle power consumption6.2W5.6-7.6W
Native Command Queuing?YesNo
Warranty lengthThree years

The most hyped difference between the two drives is the T7K250's support for 300MB/s transfer rates. Serial ATA's new 300MB/s transfer rates are commonly referred to as SATA II transfer rates, but that is apparently something of a misnomer. The officially sanctioned brand name for the higher transfer rates is actually just "3Gb/s." That's spectacular, except that we prefer to talk about storage interface speeds in megabytes per second rather than megabits per second. So we'll refer to the new SATA transfer speed in terms of MB/s, and just to keep you guessing, we'll account for SATA's built-in overhead and call it 300MB/s, even though a true 3Gb/s would be slightly faster.

Confused yet? It gets better. With internal and sustained transfer rates well below Serial ATA's original 150MB/s interface speed, this drive may be hard pressed to take advantage of the faster interface. Smaller burst transfers that fit into the drive's 8MB cache may benefit, though. We'll be testing the drive with both 150MB/s and 300MB/s interface speeds to find out.

Although perhaps not as flashy as its higher interface speeds, the T7K250's denser 125GB platters may be the drive's most valuable attribute. The new platters pack 56% more data into the same area than 80GB platters, allowing the drive head to access a given amount of data over a shorter distance. Higher areal densities are probably the most important means of boosting hard drive performance without going to higher spindle speeds. Oddly, though, the T7K250 isn't offered in larger capacities than the 7K250. In fact, it's actually offered in fewer capacities overall. Those craving greater storage capacity may be better served by HGST's 7K500 500GB, which offers double the storage capacity of the largest T7K250.

The T7K250 also supports Native Command Queuing (NCQ). Command queuing can offer significantly better performance in multi-user environments with loads of outstanding I/O requests, but it may not be as useful in less demanding single-user environments. However, as AMD and Intel's new dual-core processors encourage a greater degree of multitasking in the mainstream, command queuing may get a chance to flex its muscles in single-user systems, as well.

Like its predecessor, the T7K250's warranty coverage extends for three years. That's not quite as impressive as the five-year warranty Seagate includes with its hard drives, but it's better than the stingy one-year coverage hard drive manufacturers tried to get away with a few years ago.

Hard drives usually aren't much to look at, unless you're willing to crack them open, but I've snapped a few pictures of the T7K250 for any fetishists out there. Note that the drive has a four-pin Molex power connector for compatibility with older power supplies.