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 whereor whetherthey may have an impact on performance.
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 rate||300MB/s||150MB/s|
|Internal transfer rate||105.4MB/s||94.6MB/s|
|Sustained transfer rate||32.9-67.8MB/s||29.7-61.4MB/s|
|Average read seek time||8.5ms||8.5ms|
|Average typical seek time||8.5ms||8.8ms|
|Average rotational latency||4.17ms||4.17ms|
|Available capacities||160, 250GB||80, 120, 160, 250GB|
|Idle acoustics||2.8 bels||2.6-3.0 bels|
|Idle power consumption||6.2W||5.6-7.6W|
|Native Command Queuing?||Yes||No|
|Warranty length||Three 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.