INTRODUCTION

    Ever since the very first consumer SATA SSDs made their debut just under 20 years ago there have been many in the industry who supported the notion that mechanical disk drives (HDDs) would cease to exist sooner rather than later. SSDs have always offered immensely higher read & write performance, far lower access times and the lack of mechanical parts usually meant better reliability so in a way that made sense. Still, I was always skeptical about that for two main reasons, capacity and cost and well, it's now 2025 and HDDs don't seem to be going anywhere. Earlier this year Seagate unveiled their latest 30TB HDDs aimed towards Data Centers and professionals and with me I have the Exos M (3+) model.

    Seagate is a global leader in mass-capacity data storage, having delivered over 4.5 billion terabytes of capacity over four decades. From edge to core to cloud, Seagate builds trust in data by delivering scalable, sustainable, and secure storage solutions. Learn more at www.seagate.com.

    The brand new Exos M hard disk drives by Seagate are helium sealed models powered by CMR (conventional magnetic recording) technology paired with HAMR via their Mozaic 3+ technology. The Mozaic 3+ technology was unveiled by Seagate a few years back (they've been working on it since long before 2016) and what it basically does is to allow for more data density than ever before while at the same time improving reliability and reducing power consumption (thus carbon footprint). In order to achieve this result Seagate is using superlattice platinum-alloy media for the platters together with a plasmonic writer (nanophotonic laser, photonic funnel and quantum antenna combination), Gen 7 spintronic reader and a 12nm integrated controller. Seagate has plans for 4TB, 5TB and 6TB capacities per platter in the coming years which compared to the 3TB maximum for PMR/CMR drives is also a huge improvement (yes, the 30TB capacity Exos M model features a total of 10 platters). As for specifications the platters of the Exos M 30TB spin at 7200RPM, it has 512MB of multi-segmented cache and has a maximum sustained transfer rate of 275MB/s. Finally, Seagate covers the Exos M with a 5-year limited warranty and reports an MTBF (meantime between failures) of 2.5 million hours with a reliability rating of 0.35%.

SPECIFICATIONS AND FEATURES

THE EXOS M 30TB

Typically, I received my sample inside a static-free bag as seen above.

On a large sticker at the top of the drive we find details along with its serial number and barcode.

Turning over the drive we find a tiny PCB which means that once again all of the vital components are placed on the interior for maximum protection.

The usual SATA III (600 - 6Gb/s) power and data connectors are located at the rear of the drive right next to three pins (probably used for firmware updates).

Details on the drive thanks to Crystal Disk Info are available above.

For anyone wondering available space is around 27.2TB.

TEST BED

TESTING METHODOLOGY

     Thoroughly testing hard disk drives may require time and patience but that's just about it. Of course, that doesn't mean that one must take it lightly, at least not when people base their decision on your results. True some choose to only use 2 or 3 benchmarking suits in order to measure the performance of a drive or drives since quite honestly most benchmarking suites do tend to agree with each other (so it's not really wrong) but I've always liked taking things a step further in order to be almost 100% certain of the results I get and post in the charts.

     So, in this kind of reviews I'll be using a total of 7 different benchmarking suites in an effort to bring you the most accurate results across the board. Now the only reason why i say effort is because real-world usage is not always on par with what results one gets by running several benchmarks on a drive and that's mainly because there are many variables at work from ambient temperatures to hardware configurations and even firmware versions. The benchmarking applications use are AIDA64 suite (former Everest Pro), HD Tune Professional (as of October 2016 seek times of 3.5” drives are also recorded), HD Tach RW, ATTO*, Sisoftware Sandra Titanium, Crystal Disk Mark 64bit* and the PCMARK 7** (secondary storage suite). These benchmarking tools are the best in what they do and as you will also see later on their results more or less agree. Each test is performed a total of 6 times and then the average is recorded into the charts. Temperatures are recorded using Hard Disk Sentinel and after 45 minutes of continuous testing in a 23 degrees Celsius temperature controlled room. Finally, I also make use of the ExTech HD600 dBA meter on each of the drives (2-5cm away) in order to accurately record their noise levels (during access), although if you don't turn off all system fans when doing so it's quite possible that you will never even hear the drive. The operating system used is a fresh installation of Microsoft Windows 10 Pro with every update installed up until the time of testing.

* As of August 2025, I'll be introducing extra tests with ATTO v5.00.2 and Crystal Disk Mark v9.0.1.
** Support for PCMARK 7 has been discontinued since 2020 but it's still valid for SATA & SAS drives.

TEST RESULTS - AIDA64 / ATTO

TEST RESULTS - HD TACH RW / HD TUNE PRO

TEST RESULTS - SISOFTWARE SANDRA TITANIUM / CRYSTAL DISK MARK X64

TEST RESULTS – PCMARK 7 PRO / TEMPERATURES / NOISE LEVELS

CONCLUSION

    My last encounter with a Seagate drive was back in 2019 when they had released their very first 16TB models and so jumping from that to 30TB is a first for me. Yes, HDD performance hasn't really changed since then as evident from my charts (which is why I’ll keep including the same ones I had in 2019) but since we're entering the era of massive capacities I decided to also add extra tests for more demanding audiences, more specifically 32GB tests using the latest version of ATTO (v5.00.2) and 64GB tests using the latest version of Crystal Disk Mark (v9.0.1). Now I don't have every single HDD I've reviewed to date in the lab, so I just benchmarked the ones I've kept. With all of these out of the way it's clear that the Exos M 30TB model by Seagate is among their fastest models to date, if not the fastest one. Not only did it reach over 290MB/s during my tests it also produced the 3rd fastest seek times behind the Exos X16 and Enterprise Capacity 3.5 V6 models again by Seagate. That's not all however since I also recorded the least noise from all the drives in my charts while testing the Exos M and even though that's not a game changer it's always nice to see improvements across the board (which HAMR obviously offers).

    With a retail price set at USD599.99 inside the USA (Amazon.com) and at 624.17Euros inside the EU (Amazon.de) it’s very easy to see why HDDs offer a much higher capacity/cost ratio compared to SSDs. Granted, performance is not even close when comparing M.2 NVMe SSDs to a SATA III HDD but when capacity is the primary concern the latter has the lead (just for the record, the Exos M 30TB costs roughly the same as an 8TB Gen4 M.2 NVMe SSD). Overall, I can’t think of a single bad thing to say about the Exos M 30TB enterprise-grade HDD by Seagate. So far HAMR via their Mozaic 3+ technology pans out and since it does offer the highest capacities currently the Exos M 3+ 30TB deserves the Platinum Award.

 PROS

- Impressive Build Quality / Durability (2.5 Million Hours MTBF)
- Top Of The Charts Performance (SATA III)
- Technologies Used (Mozaic 3+ / PowerChoice / PowerBalance)
- 512MB Cache
- Massive 30TB Capacity (Up To 36TB Currently)
- Temperatures / Noise Levels / Power Consumption
- 5 Year Limited Warranty

CONS

- Price (For Some)