Seagate Exos M 30TB HDD review: laser-powered HAMR recording tech revitalizes the enterprise HDD market

Why you can trust Tom’s Hardware

Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

If you’ve been waiting for that next leap in storage capacity, your patience has paid off. Seagate has launched its 30TB drives in both the Exos and IronWolf Pro lines, with larger capacities yet to come. This represents a significant leap forward from the previous generation’s 24TB limit, with special attention paid to power consumption. It’s never been possible to get more storage in a smaller footprint for HDDs than this, and that’s thanks to the firm’s new laser-driven tech. Seagate employs its new laser-powered heat-assisted magnetic recording (HAMR) technology with this drive, a first for a mass-market enterprise hard drive.

The Mozaic 3+ technology platform enables an unprecedented amount of storage density by using a laser to heat a small area of the disk to 450°C (842°F) before recording data to it, thus allowing bits to be packed into a smaller area. For end users, there is no difference in use, performance, or reliability.

Seagate has unveiled drives of up to 36TB for shingled magnetic recording (SMR), which comes with performance penalties, and 32TB for the more performant conventional magnetic recording (CMR), so far without an overwhelming increase in power consumption. This is exciting news for storage enthusiasts who want to get the most storage in the smallest space by using the fewest drives possible. Large data, particularly with evolving AI workloads, is becoming an everyday part of life for businesses, home labbers, and data hoarders alike. SSDs remain prohibitively expensive unless there are specific performance needs, so HDD tech continues to march forward.

If you are truly looking for the largest HDD possible, it’s certainly worth looking at the Seagate Exos M and IronWolf Pro. Although both drives are great for enterprise, home users may be better off with the latter, especially for NAS. If you can get by with smaller drives, especially a larger count of smaller drives, then some money can be saved by opting for the last generation of 20TB-24TB HDDs, although at some points, the price per terabyte gets quite close. But let’s see what the Exos M brings to the table in terms of performance.

Seagate Exos M Specifications

Swipe to scroll horizontally

Header Cell – Column 0	Seagate Exos M 30TB	Seagate Exos M 28TB
Capacity	30TB	28TB
Model #	ST30000NM004K	ST28000NM003K
Pricing	$599.99	$569.99
Cost per TB	$20.00	$20.36
Interface	SATA 6 Gb/s	SATA 6 Gb/s
Form Factor	3.5″	3.5″
Technology	CMR	CMR
RPM	7,200	7,200
Sustained Transfer Rate	275 MB/s	270 MB/s
Cache	512MB	512MB
Operating Power	9.5W (6.9W Idle)	9.5W (6.9W Idle)
Noise	34dB (Max)	34dB (Max)
Workload Rate Limit
MTBF	2.5M hours	2.5M hours
Warranty	5-Year	5-Year

Through the use of 3TB+ platters, the Seagate Exos M is available at 28TB/30TB for CMR and 32TB/36TB for SMR. 24TB and 32TB models for CMR are also listed in the product manual, but are not currently available. We’re looking at the 30TB CMR part today, as many users do shy away from SMR when possible.

30TB is the largest hard drive we’ve tested to date, and it doesn’t come cheaply, with pricing at $569.99/$599.99 for the two CMR capacities. The 30TB model can achieve sustained write speeds of up to 275 MB/s at 7,200 RPM with a 512MB cache – this is as good as it gets. Seagate’s warranty covers the drive for five years with a maximum workload rate limit of 550TB per year.

At ~$20 per TB or ~$0.020 per GB, you are paying a premium against drives like the Seagate BarraCuda, the WD Red Pro, as well as Seagate’s SkyHawk AI, IronWolf Pro, and Exos X20. Then again, none of those drives reach this capacity, and the highest capacities for these drives are not too far off from this price. Better deals can definitely be had if you’re willing to compromise in one area or another – like the warranty – but this drive is essentially at the top for storage density at the moment.

Seagate Exos M Software and Accessories

Seagate’s site has SeaTools and DiscWizard available for the Exos M. SeaTools is available for Windows and Linux, and also comes in a bootable form. Natively, this has a GUI, but there is a comprehensive CLI guide available. It allows for maintenance of the HDD through diagnostics and monitoring. DiscWizard, on the other hand, is a Windows application that guides you through the process of preparing your drive, which includes formatting, partitioning, and data transfer and backup.

Seagate Exos M: A Closer Look

Image 1 of 2

Seagate Exos M 30TB HDD — (Image credit: Tom’s Hardware)

We see three Winbond ICs on the drive PCB. The first is labeled W634GU6QB-12 with the “4G” for 4Gb, or 512MB, and the “6” indicating a 16-bit rather than 8-bit configuration. This is a volatile DDR3L cache for the drive. The second is labeled 25N01GWZEIG, which is “1G” or 1Gb, that is 128MiB, of SPI non-volatile SLC NAND flash for the controller. Lastly, we have a 32Mbit or 4MiB package of NOR flash also for the controller. SSDs, for their part, also have integrated memory to handle booting and firmware execution.

previous Seagate HDD reviews. Seagate continues to improve on this technology, which is effectively a memory hierarchy utilizing some intelligence to improve drive performance. This is workload-dependent, which incorporates I/O size and type into the drive’s calculation of how to cache the data. Improvements here are built on top of Seagate’s refined HAMR implementation, or what they call the Mozaic 3+ platform, which essentially enables higher capacities. The main goal is to squeeze as much capacity out as possible without making the drives unusable in terms of performance or power consumption.

Image 1 of 2

Looking more closely, we see the SMOOTH Thor controller, which is the motor driver and power management IC for the drive, manufactured by STMicroelectronics. The other chip is Seagate’s controller/ASIC, made in 12nm, which manages the drive in a way comparable to an SSD controller. Together, these handle drive functions and operation and are separate from the media itself. SSDs also feature power management, often with PMICs, and often include a separate NAND flash controller as part of the main ASIC. SSDs also have separate NAND flash packages for their media and may or may not have a DRAM cache, but such caches are used for metadata, while HDDs use them for write caching.

MORE: Best SSDs

MORE: Best Hard Drives

MORE: Best SSD for the Steam Deck