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

Comparison Products

Right now, the only other 30TB we’ve had on our testbed is the Seagate IronWolf Pro. For the sake of comparison, we’ve included the previous generation of drives, including the 22TB WD Gold, the 20TB WD Red Pro, the 20TB Toshiba X300 Pro, the 20TB Seagate SkyHawk AI, plus the 20TB Seagate Exos X20 and IronWolf Pro. These hard drives are not all targeting the same market segments. The WD Gold is an enterprise drive like the Exos serie,s while the Red Pro and IronWolf Pro lean more towards NAS. The SkyHawk is for surveillance systems, like WD’s Purple line, while the X300 Pro is designed for workstations.

Usually, if you’re looking at cutting-edge drives in terms of capacity, you are less concerned about other factors like price. You may pay more attention to power efficiency and heat generation, as well as specifications for noise and vibration. Nevertheless, new technology should be compared to the old to identify improvements beyond capacity alone. HDDs tend to only have iterative advances from generation to generation, which can make the decision process more focused on the user rather than the drive – that is, storage is an investment with wider goals than any single drive or solution.

Trace Testing — 3DMark Storage Benchmark

Built for gamers, 3DMark’s Storage Benchmark focuses on real-world gaming performance. Each round in this benchmark stresses storage based on gaming activities including loading games, saving progress, installing game files, and recording gameplay video streams. Future gaming benchmarks will be DirectStorage-inclusive and we also include notes about which drives may be future-proofed.

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Who doesn’t love the idea of a 30TB drive just for games? Unfortunately, games these days benefit massively from SSDs, with many even requiring them. Your load times will generally be abysmal with an HDD, even a fast one, although there are exceptions. You’re more likely to use an HDD like this to build a game with compressed assets than to play one.

In any case, the Exos M returns average performance in 3DMark. Previously, we would recommend the 8TB Seagate FireCuda if you really want to use an HDD for gaming, but unfortunately, it is currently difficult to find that drive. You can get a 12TB WD Blue direct from WD, though, with CMR technology at 7,200 RPM as a good alternative.

Trace Testing — PCMark 10 Storage Benchmark

PCMark 10 is a trace-based benchmark that uses a wide-ranging set of real-world traces from popular applications and everyday tasks to measure the performance of storage devices. The results are particularly useful when analyzing drives for their use as primary/boot storage devices and in work environments.

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You probably also don’t want to be using an HDD for your primary or boot drive. You’ll have a much better experience with an SSD. However, HDDs can be useful for asset storage, archiving, and more for your applications. They are also fast enough to record sequential streams if you like to record videos or gaming sessions. Anything latency-sensitive is out of the question, though.

Transfer Rates — DiskBench

We use the DiskBench storage benchmarking tool to test file transfer performance with a custom, 50GB dataset. We write 31,227 files of various types, such as pictures, PDFs, and videos to the test drive, then make a copy of that data to a new folder, and follow up with a reading test of a newly-written 6.5GB zip file. This is a real world type workload that fits into the cache of most drives.

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We are a little disappointed in the Exos M’s copy performance, but we can see that this is from the poor read transfer rate. We know the drive can read a lot faster than this sequentially, so the nature of our test throws it for a loop. We would not recommend using a drive for storage/transfers involving a lot of smaller files, anyway, and ultimately, the difference in copy rate isn’t massive in DiskBench for HDDs. Larger, compressed files make more sense as long as the data is considered at least a little bit cold – HDDs remain superior if data access is less frequent.

Synthetic Testing — ATTO / CrystalDiskMark

ATTO and CrystalDiskMark (CDM) are free and easy-to-use storage benchmarking tools that SSD vendors commonly use to assign performance specifications to their products. Both of these tools give us insight into how each device handles different file sizes and at different queue depths for both sequential and random workloads. These tests can also be useful for comparing HDDs, too.

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Hard drives, and this drive in particular, like larger block sizes. Optimally, you would be working with 1MiB or larger files to get peak performance. However, HDDs have no real problem starting as small as 32KiB. This applies to both reads and writes, as demonstrated by the ATTO benchmark.

CrystalDiskMark’s sequential tests use 1MB blocks by default, and we can see the Exos M dominate the rest of the field. Perhaps 'dominate' is too strong a word, but it does grab first place regardless of operation type or queue depth. It’s worth pointing out that queue depth isn’t as useful for HDDs in these tests compared to SSDs, which is important to recognize because file transfers are often QD1 and sequential. That said, Seagate emphasizes that the Exos M is optimized for multi-stream, mixed-use I/O with higher queue depth, but we’re still generally talking larger I/O.

Random performance, on the other hand, is relatively abysmal, but that’s expected for 4KB files on any HDD. The Exos M is designed for relatively large data chunks, as used in AI and other data-heavy applications. Seagate has optimized the drive to some extent to handle small I/O, particularly with queue depth, but you can’t expect miracles. This isn’t too surprising, as enterprise data patterns are often larger, even on SSDs with indirection unit sizes of 16 KiB or 32 KiB for QLC flash drives.

Sustained Write Performance and Cache Recovery

We use Iometer to hammer the HDD with sequential writes for 15 minutes to measure both the size of the write cache and performance after the cache is saturated. We also monitor cache recovery via multiple idle rounds. This process shows the performance of the drive in various states as well as the steady state write performance.

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HDDs aren’t quite as exciting as SSDs when it comes to our sustained write test. While SSDs can be all over the place due to the nature of pSLC caching, HDDs are much more consistent. The Exos M comes out on top, which is not too surprising, as larger HDDs tend to be as fast as or faster than previous lower-capacity models. The difference here is rather small, though, so if this is a realistic workload for you, then you can get by with a smaller drive – unless you need a lot of storage in a limited space and are factoring power consumption into your equation.

Power Consumption and Temperature

We use the Quarch HD Programmable Power Module to gain a deeper understanding of power characteristics. Idle power consumption is an important aspect to consider, especially if you're looking for a laptop upgrade as even the best ultrabooks can have mediocre stock storage. Desktops may be more performance-oriented with less support for power-saving features, so we show the worst-case.

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Seagate touts the high power efficiency of this model, and we must say that, although it appears unfavorable on our charts, the capacity needs to be factored in. This benchmark is based on our DiskBench test, which inherently disfavors the Exos M. The Exos M is barely the fastest drive in sustained sequential writes, too. This means that our average power consumption results are closer to the mark, and while the Exos M is still at the bottom, it’s not too far off from drives that have 33% less capacity.

Consider that you need six 20TB Red Pros for four 30TB Seagate Exos M drives. Given that the workload rate limit (WRL) is essentially in the same ballpark, the fact that the Exos M isn’t particularly impressive in terms of performance is less critical. You’re picking this drive to maximize storage density instead, with relatively predictable workloads – smaller random writes will be cached in the volatile DRAM, too. We would still like to see better numbers here, but in terms of expected workloads, the Exos M holds its own.

Seagate itself claims that power consumption per terabyte is down as much as 45% which, when combined with the relatively modest cost per terabyte, means a lower total cost of ownership (TCO). This is derived from, in part, its PowerChoice technology, which increases the number of power states, especially in idle, to save power wherever possible. Our idle consumption test is more aggressive, but given the WRL, you will likely see better power savings than what is expected from our results. Heat generation derives from power consumption, so the important thing is that the 30TB Exos M shouldn’t challenge existing cooling infrastructure.

Test Bench and Testing Notes

We use an Alder Lake platform with most background applications such as indexing, Windows updates, and anti-virus disabled in the OS to reduce run-to-run variability.

Seagate Exos M Bottom Line

The Seagate Exos M hard drive is an accomplishment, but its place in the market has to be understood within the context of high-capacity storage. You’re not buying this drive for performance alone but rather for a lower total cost of ownership. A larger drive means more data in the same footprint, and maintaining the same performance level without adding any burdens means that workload optimization and power consumption improvements are required. This isn’t as complicated as all the new fancy technology details insinuate from the end user’s viewpoint, as fundamentally, the Exos M offers storage density without trying to do things outside of what HDDs do.

The drive sufficiently makes its case with reasonable performance where it matters and pricing that isn’t ridiculous. If you need the most amount of storage possible for a given space, the Exos M is likely your answer. The IronWolf Pro line is similar and might be a better choice for home users and NAS, while the Exos M leans more toward enterprise. In either case, you can get the same or more storage at the Exos M’s price per terabyte if you’re willing to go with the last generation of drives. This could make sense if you have drive bays to spare. If you’re a regular user, on the other hand, you're likely to look elsewhere, as $600 is a steep entry point.

One thing we would like to point out is that this drive is and will continue to be available with both CMR and SMR technologies. SMR allows for even higher capacity but has significant performance caveats. Know your workloads before you pull the trigger.

As far as the CMR Exos M goes from our review today, performance is largely as expected, and some of Seagate’s optimizations – with multi-tier caching and improvements for idle power states – may be more significant for your specific use case. Just don’t read too much into it, as at the end of the day, an HDD is an HDD, and for now, this is the biggest of them all.

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