We may be reaching the very limits of what’s possible with current hard-disk technology. But that hasn’t stopped Hitachi from becoming the first storage company to market with a four terabyte disk drive.

In fact, while other vendors – namely Seagate and Western Digital – are promising 3.5in disks at this almighty capacity level, there are only two 4TB disks available as of late March. And they’re both from Hitachi GST.

First to market was the Hitachi Deskstar 5K4000, a low-power version of the Deskstar that’s optimised for quieter operation and reduce power consumption. Hitachi doesn’t publish the spindle speed, but it’s likely to around 5400rpm, the same as most notebook disks.

Second to market was the Deskstar 7K4000, a regular 7200rpm spec disk that’s already appearing in the G-Technology G-RAID With Thunderbolt external drive.

The slower drive features what Hitachi calls CoolSpin technology, which optimises motor speed in order to balance peformance with power requirements and acoustic noise output. The spec sheets give a 1.5A (12V) maximum current for startup, which is usually the peak requirement. Noise levels are usefully low, at a given 25dB. That’s comparable to a quiet notebook drive.

We tested the Hitachi Deskstar 5K4000 on our standard lab machine, optimised for HDD and SSD measurements. In the basic ATTO Disk Benchmark test, performance plateaued with all test data from 8kB up to 8MB. Here we saw sequential reads reach 132 MBps, and writes up to 134 Mbps.

Plotting read/write speeds against capacity level, the HD Tune Pro test showed how performance tails off as the disk is filled. When empty, the 5K4000 peaked at 131 Mbps for reads and writes. When reaching it capacity it hit its minimum, where transfers fell to just half with 64 MBps. The disk average was 103 MBps. Access time recorded here averaged 19ms.

Turning to CrystalDiskMark, the headline speeds were 133 MBps for read and writes, falling to 47 and 67 MBps respectively for 512kB data, and 0.59 and 1.64 MBps for the smallest 4kB traffic.


Hitachi’s Deskstar 5K4000 is not the fastest hard disk on the planet. But, along with its speedy sister disk the 7K4000, it is the largest. Performance nonetheless is very good for a ‘low power’ slower spinning desktop drive, very comparable to the full speed hard drives of just a few years ago. A colossal amount of storage capacity in a 3.5in disk that’s little louder than a laptop drive is quite a feat.