Seagate recently brought back its BarraCuda line with new 10TB 3.5" models, and now it has added beefy 5TB 2.5" models that are the first 2.5" HDDs to break the 5TB barrier. Seagate also increased the density of its FireCuda 2.5" SSHDs up to 2TB.
BarraCuda 5TB 2.5" HDDs
Seagate designed the BarraCuda 2.5" line for high-performance applications (at least as high-performance as HDDs can be) with capacities that range from 500GB to 5TB. The 3TB, 4TB, and 5TB models feature a 15mm Z-height (thickness), so they won't slip into the overwhelming majority of laptops. Seagate offers the thicker 2.5" models for external use cases, such as enclosures or drive docks. Of course, a 15mm 2.5" drive will fit nicely into a computer case, so it might be useful for SFF applications, although you might need an adapter. The 500GB, 1TB, and 2TB models feature the 7mm Z-height, which allows them to fit inside laptops.
The SATA 6Gbps BarraCuda series uses standard PMR (Perpendicular Magnetic Recording), which is a nice surprise, as we expected the company to use SMR (Shingled Magnetic Recording) for the 5TB model. (EDIT: The drive is an SMR drive, but Seagate omitted that designation in its manual. Seagate representatives indicate the company will correct the manual. More detail here.) SMR suffers performance disadvantages during random write workloads, but the faster PMR technology allows the drive to offer faster, more responsive performance in diverse workloads.
The Power Bits
The 2.5" BarraCuda models have a 5,400RPM spindle speed that limits the data transfer rate to 140MB/s, but the slower spindle speed helps reduce power consumption. The entire range of BarraCuda 2.5" HDDs have an average 1.9/2.1W read/write power consumption rating and idle/sleep at 1.1W/.18W. HDDs require a big "jolt" of energy to get started, which could limit applications in power-constrained USB 2.0 external enclosures. Seagate limited the startup current to 1.2A, which allows the company to retain backward compatibility with legacy enclosures.
| Header Cell - Column 0 | 5TB, 4TB, 3TB | 2TB, 1TB, 500GB |
|---|---|---|
| Model Numbers | ST5000LM000, ST4000LM024, ST3000LM024 | ST2000LM015, ST1000LM048, ST500M030 |
| Spindle Speed | 5,400 RPM | 5,400 RPM |
| Z-Height (Thickness) | 15mm | 7mm |
| Data Transfer Rate (MB/s) | up to 140 | up to 140 |
| Startup Current (A) | 1.2 | 1.0 |
| Idle/Sleep Power (W) | 0.18 | 0.18 |
| Average Power Read/Write (W) | 1.9/2.1 | 1.7/1.8 (2TB) - 1.6-1.7 (1TB, 500GB) |
| Cache | 128MB | 128MB |
| Interface | SATA 6Gbps | SATA 6Gbps |
| Warranty | 2-Year | 2-Year |
As expected, the drives also have 128MB of cache, a somewhat relaxed UBER rating of 1 per 10E14, a 55TB per year workload rating, and two-year warranty. Surprisingly, the drive has a 600,000 cycle load/unload rating, which provides more than enough durability for external use.
The Density Bits
Seagate is using the 1TB platter technology it announced earlier this year (1,307 Gb/in2 average areal density) to achieve the increased density. The 5TB model features five platters and ten heads. The drives also use standard air-based technology, in contrast to the helium designs that have yet to penetrate the 2.5" segment. A combination of SMR and helium could theoretically offer much higher density, so there is still room for further density enhancements beyond 5TB with existing technology. HDD vendors tend to use a base HDD design for several products with various performance ratings, so it is reasonable to expect 2.5" 5TB 7,200RPM enterprise models in the future.
Seagate's move to high-density 2.5" products is essential as it attempts to stave off denser SSDs. The 2TB limit in the 2.5" 7mm form factor continues to be a sore spot, as Samsung already has 4TB SSDs with the same measurements. HDDs still enjoy a significant price advantage, however: A 4TB Samsung 850 EVO will set you back $1,499, whereas Seagate said the BarraCuda will retail for a mere $55-$85 depending on capacity. However, SSDs continue to steal more market share in the notebook segment every quarter. Seagate's focus on the external segment is wise as it continues to retreat into "cheap and deep" applications.
The 2.5" FireCudas
Seagate is also talking up its previously announced FireCuda SSHD. Like the BarraCuda series, the FireCuda series comes in both 2.5" and 3.5" flavors. The 2.5" models previously topped out at 1TB, but Seagate announced a new 2TB model. The company injected 8GB of NAND flash into the 2.5" 1TB FireCuda, along with its Multi-Tier Caching algorithms, to boost workload performance in mainstream/gaming applications.
| Header Cell - Column 0 | 2TB, 1TB, 500GB |
|---|---|
| Model Numbers | ST2000LX001, ST1000LX015, ST500LX025 |
| NAND Cache | 8GB |
| Spindle Speed | 5,400 RPM |
| Z-Height (Thickness) | 7mm |
| Data Transfer Rate (MB/s) | up to 140 |
| Startup Current (A) | 1.0 |
| Idle/Sleep Power (W) | 0.18 |
| Average Power Read/Write (W) | 1.7/1.8 (2TB) - 1.6/1.7 (1TB, 500GB) |
| DRAM Cache | 128MB |
| Interface | SATA 6Gbps |
| Warranty | 5-Year |
We consider 8GB of NAND to be anemic for the 1TB FireCuda, as the desktop SSHDs feature up to 32GB of flash. Seagate curiously chose to stay with the same 8GB NAND package for the new 2TB model.
The Multi-Tier Caching algorithms dynamically identify "hot" (frequently requested) data and promote it to, or evict it from, the NAND cache accordingly. However, if a user requires data that isn't held in the cache, they notice a measurable performance decline as the drive recovers the data from the spinning platters. More cache allows the drive to accelerate more data, so the size of the cache has a profound performance impact.
We think a sizable bump in NAND capacity, perhaps as high as 64GB, would help speed SSHD adoption. SSHDs really haven't taken off, but Seagate intends to keep plucking away with its speedy SSD alternatives. The FireCuda features a 5-year warranty and is available now. Seagate indicated the 2TB FireCuda will retail for $85-$95.
EDIT 11:20am PST 11/17/2016 - The 5TB BarraCuda is an SMR drive, but Seagate omitted that designation in its manual. Seagate will correct the manual. More detail here.)
