Capacity Marches Forward, Commands A Premium
Hitachi could be the only hard drive manufacturer with internal 4 TB disks for a few months longer. Seagate has its own 4 TB model, but is only putting it into external enclosures. Western Digital's Caviar Green family could also receive a facelift soon, moving into the 4 TB space. Not surprisingly, capacities will continue marching forward, and that's a great thing for businesses and enthusiasts with burgeoning capacity needs.
In the end, everyone benefits when drive vendors engage in capacity wars, even if most of us only end up buying more mainstream disks. Seagate is a great example of this. While its 1 TB platters potentially enable seriously large drives, even smaller models benefit, coming in at lower prices, generally using less power, and often proffering better performance. Additionally, the ability to put 1 TB on a platter makes it that much easier for entry-level PCs to include at least that much storage space (the sweet spot) using a low-cost disk.
Performance? Seagate Barracuda
The fastest 3.5” high-capacity desktop hard drive in this round-up is Seagate’s new 3 TB Barracuda (ST3000DM001). It offers almost 200 MB/s sequential read performance, similar write speeds, and it runs relatively coolly thanks to its three-platter design.
However, Seagate didn't design this Barracuda for 24/7 operation. If you need higher availability, you'll want to check out Seagate’s Barracuda XT or Hitachi's Deskstar 7K3000. Both are five-platter designs, robust, and still fast enough for video editing or video surveillance servers. Three terabyte hard drives are probably the best compromise between capacity and cost, as 2 TB disks might not always be big enough and 4 TB models are still very expensive.
Capacity? Hitachi Deskstar
If you're willing to live with that sizable price premium in the name of massive capacity, there are only two options available to you right now: Hitachi's Deskstar 5K4000, a 5400 RPM drive, and the 7200 RPM Deskstar 7K4000. The latter is a solid all-around performer and it's rated for 24/7 availability. The 5K4000 understandably sacrifices performance, but it’s also one of the most efficient drives if you’re looking for low-power storage.
In that context, you could also consider Western Digital's Caviar Green, though it gives up even more performance and it's not specified for high availability.
Hard Drive Performance Evolves Slowly
This bears mention again: when we look at the performance of mechanical disks and the rate at which they improve, we're reminded that SSDs are disruptively faster and more responsive. New throughput records are being broken all of the time, and we're already butting up against the limits of today's highest-bandwidth desktop interface, SATA 6Gb/s.
Meanwhile, even after picking up 20% more throughput, today's latest hard drives aren't even able to saturate a last-generation 3 Gb/s connection. When it comes to access times and I/O performance, neither metric speeds up at all compared to the last round of drives we reviewed.
Simply, the mechanical arms equipped with read and write heads cannot be sped up and slowed down at will; there are physical limits. Trying to be more aggressive reduces the life span of a drive, and even a small gain won't help stave off SSDs in a performance comparison. The results of our testing clearly shows that hard drive vendors don't bother trying to optimize for access times or I/O anymore. It's futile.
This is not going to change, which is interesting because the industry won't be replacing magnetic hard drives with anything else in the predictable future. Disks will continue to provide more capacity at low cost, as today's computing experience is decreasingly limited by CPU or GPU power and more dependent on storage. Pushing I/O is the key there, meaning that any workload relying on frequent accesses should increasingly rely on flash-based devices, while hard drives safeguard our digital memories and databases.
Three terabyte hard drives continue to offer the best cost per gigabyte of storage space. Two terabyte drives offer even better value at similar performance levels. Four terabyte disks are a good option when you need big capacity and don't have space for multiple 3.5" devices. However, their price premium keeps us from recommending broader adoption.