WD Gold 22TB HDD Review: The Gold Standard?

WD’s 22TB Gold HDD has arrived in our labs. WD has segmented its products with a basic color scheme from Green to Blue, Blue to Black, and Black to Gold – with Gold being the high-end enterprise hard drive storage solution. It’s the pinnacle of the product stack with the very highest capacities, the highest sustained transfer rates, and all of the top features – like the new ArmorCache – for performance and reliability. It’s potentially the best HDD you can buy, but it’s also not meant to replace your Blues and Blacks, or your SSDs, for that matter. It’s made for multi-drive, high-performance environments where uptime and data integrity are of paramount importance.

WD has other models, too, like Purple for surveillance and Red for NAS. These two are technically closer to Gold in the hierarchy, being almost lateral siblings. The Red Pro and Purple Pro have OptiNAND technology at 22TB. Green, for its part, has been effectively phased out as the Blue line has taken up the slack for budget, low RPM solutions. The consumer lines have a capacity limit of 10TB with the Black. This leaves Gold for the enterprise-class with extreme capacity, reliability, and performance. While larger capacities are on the way, 22TB is currently the highest offering – and also the first drive to use WD’s OptiNAND-based ArmorCache technology. This might be the 22TB Gold drive’s real standout feature.


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Product Western Digital Gold HDD
Capacity 22TB
Model # WD221KRYZ
Pricing $549.99
Cost per TB $25.00
Interface SATA 6 Gb/s
Form Factor 3.5″
Technology CMR
RPM 7200
Sustained Transfer Rate Up to 291 MB/s
Cache 512MB
Operating Power 7.1W
Noise 32 dBA (seek avg)
Workload Rate Limit 550TB/Yr
MTBF 2.5M hours
Warranty 5-Year

The WD Gold HDD is available in a variety of capacities, starting at 1TB and currently going all the way up to 22TB. We’re looking at the latter today, a SKU that sets itself apart from the rest as it alone has the ArmorCache feature. The drive is otherwise your standard 3.5”, 7200 RPM HDD, able to reach up to 291 MB/s sustained with an ample 512MB DRAM cache. It’s an enterprise drive, and so it has a full five-year warranty along with a 2.5 million hours MTBF rating and a workload rate limit (WRL) of 550TB per year. Currently, this is priced at $549.99, although you can save some money with the right discount.

22TB is still a very high capacity for hard drives, even with plans for 30TB and more on the horizon. As such, you pay a premium, and there are not many alternatives to the WD Gold. WD’s own Purple Pro is about $100 less expensive right now and has very similar technology, but it lacks ArmorCache and also has a reduced sustained transfer rate of 265 MB/s. This is also true of the Red Pro, available at 22TB for even less than the surveillance-oriented Purple Pro. Seagate has its IronWolf Pro and Exos X22, also at reduced cost in comparison, but these do not have WD’s OptiNAND technology and also have no ArmorCache feature.

Software and Accessories

WD has two downloads on its site for HDDs: the Western Digital Dashboard and Acronis True Image for Western Digital. The first allows you to analyze disk attributes including SMART and drive firmware. The second is used to backup, clone, and image systems and files/folders with an OEM version of Acronis True Image. This comes with a five-year license.

A Closer Look

The WD Gold certainly doesn’t look special. HDDs, in general, are not as diverse as SSDs in this respect. Some WD HDDs do stand out internally, including the 22TB Gold, as they have an onboard iNAND and a controller for the flash due to WD’s OptiNAND technology, which we covered previously with the WD Red Pro. This technology uses non-volatile flash memory to store important metadata, such as for repeatable runout (RRO) and for sector-level write operation records to reduce adjacent track interference (ATI). To put it more simply, OptiNand improves performance and allows for higher-capacity drives, although it can also reduce DRAM overhead, and associated functions may improve reliability.

Improved metadata efficiency is only part of what OptiNAND can provide. Using some of the flash, 128MB, to store data from DRAM during emergency power off (EPO) can improve drive performance without a corresponding risk of data loss. This is the crux of the ArmorCache feature. With ArmorCache and the write cache disabled (WCD), which has no data loss risk by nature, random write IOPS can reach the same level as write cache enabled (WCE) mode on normal drives. At the same time, data is safe from power loss if the drive is used in the WCE mode. This is of significant value for some use cases.

Most systems default to WCE, which can increase host/software overhead if there’s a need to ensure data integrity, and the risk of critical data loss is a significant factor to consider as well. While only 128MB of iNAND is reserved for power loss metadata, user data in DRAM is also protected as it can be written to flash during sudden power loss with the use of the remaining rotational energy of the spinning disks. ArmorCache can also be disabled in WCE mode for specific environments if desired.

The write cache can also be disabled (WCD) completely for maximum protection but with a corresponding performance loss, as all data must be guaranteed. ArmorCache can still help here, but flushing amount depends on transfer length. Applications that utilize HDDs generally deal in larger transfer sizes, and in this scenario, ArmorCache can improve random write IOPS significantly, reaching WCE performance levels. The both-mode improvements from ArmorCache let the 22TB Gold stand out from its peers.

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Comparison Products

The 22TB WD Gold faces the similar 20TB Red Pro and the lower-end 12TB Red Plus. Seagate has more direct competitors for WD’s high-end drives with their 20TB IronWolf Pro and Exos X20 series. HDDs are useful for specific applications, as demonstrated by the capable 20TB Seagate Skyhawk AI. 14TB stand-ins include the Seagate IronWolf Pro and Toshiba X300.

The Gold stands out in this group as it has ArmorCache technology, but it shares OptiNand with the Red Pro. HDDs are intended for different workloads than SSDs in most cases and may also end up in multi-tiered storage solutions, but the results here can be useful for personal investment. Nothing is stopping you from using this drive in your home systems, and if reliability is your top concern, ArmorCache might trump performance.

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.

The Gold performs about as well as its Red Plus and Red Pro siblings, which is not good but still better than the X300. HDDs should not be used for gaming at this stage, in my opinion, although they may be useful for archiving games to prevent redownloading in cases of limited Internet bandwidth. Large game collections may also benefit from a capacious HDD, but that target is usually at 8TB, with the Seagate FireCuda or maybe WD Blue, and SSDs are starting to creep up on that range.

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 Gold is merely average. We don’t recommend HDDs for everyday applications or OS use, either. At this point, it is trivial to add fast SSD storage for booting and your primary programs. If you are using HDDs for backups, your transfers should generally be sequential once packed, so the PCMark result is not super relevant there, either. However, it could demonstrate server performance in some cases.

Transfer Rates – DiskBench

We use the DiskBench storage benchmarking tool to test file transfer performance with a custom, 50GB dataset. We copy 31,227 files of various types, such as pictures, PDFs, and videos to a new folder and then follow-up with a reading test of a newly-written 6.5GB zip file.

DiskBench’s copy with a realistic file and folder workload is more useful for testing HDDs. The Gold is sufficiently fast but sets no records and falls a bit behind the other large-capacity drives.

We would like to point out that the Gold has 512MB of DRAM cache, double the 256GB found on the other 20TB drives except for the Red Pro. Other 22TB drives we’ve mentioned, the Purple Pro and IronWolf Pro/Exos X22, do have 512MB, however. This could influence the performance of certain file transfers or operations, with more DRAM being beneficial, so the 22TB Gold has that over the other drives listed here aside from the Red Pro. The Red Pro is probably the better bet for NAS, while the Purple Pro has AI-optimized firmware to make it better for video streams.

Synthetic Testing – ATTO / CrystalDiskMark

ATTO and CrystalDiskMark (CDM) are free and easy-to-use storage benchmarking tools that storage 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.

The Gold has no trouble in ATTO, although it doesn’t reach the heights expected from the datasheet. Sequential performance in CDM is also unexciting. Hard drive technology is pretty fixed in this respect, with improvements usually tied to growing capacity, aside from advances like Seagate’s Mach.2 or Exos 2X18. Which is to say, the Gold’s performance is adequate.

The Gold’s random read and random write latencies are not bad, and we do see the expected boost to random write IOPS. OptiNAND can help here, especially when write caching is disabled with the Gold’s ArmorCache feature. However, by default write caching is enabled, and that is how HDDs are usually used on personal systems.

Sustained Write Performance

Official write specifications are only part of the performance picture. Most HDDs implement a write cache which is a fast area of volatile memory such as DRAM.  Sustained write speeds directly hit the platters and tend to be consistent. There are exceptions to both of these statements as there are SSHDs (flash-containing hybrid HDDs), OptiNAND drives, and SMR drives that deviate from the traditional configuration. We use Iometer to detect the maximum sustained write speed of the HDD.

The Gold performs well but not exceptionally well, performing on the level of the Red Pro. WD specifically sells the Gold for data centers and larger storage systems, so this is more of a niche product for home and small business use. It’s likely that the Red Pro would be a better fit in many cases. However, if you are looking for reliability and this performance profile, the Gold could work for SOHO and NAS.

We tested all of these HDDs with write caching enabled. The Gold’s ArmorCache is also enabled by default, and we did not manually disable it, although it is possible to do so according to the feature’s literature. This feature is a big selling point, so if you intend to disable it for whatever reason, you can probably get 22TB at a better price point with a different model. The price trade-off makes sense as this drive is geared towards reliability, and performance-wise, it’s designed specifically for better RAID and random performance.

Power Consumption

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 storage.

Some drives can consume watts of power at idle while better-suited ones sip just milliwatts. Average workload power consumption and max consumption are two other aspects of power consumption, but performance-per-watt is more important. A drive might consume more power during any given workload, but accomplishing a task faster allows the drive to drop into an idle state more quickly, ultimately saving energy.

The Gold does take a lot of power, but this is to be expected for a 22TB enterprise HDD. It’s not egregious. This drive had no thermal issues whatsoever, staying under 30C in our testing. It’s also designed to be used in a multi-HDD environment, which includes vibration protection, and it is well-suited to that type of environment.

Test Bench and Testing Notes

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The 22TB WD Gold sits in a class of its own, even if it’s not a drive for everyone. We’d recommend the Purple Pro, instead, for surveillance use. WD’s Red Pro is an excellent choice for NAS and even general storage if you want the highest capacities and performance at a lower price. Alternatively, Seagate’s IronWolf Pro and Exos lines offer a good value if you really need 22TB per single drive, although they lack OptiNAND. In practice, this isn’t a huge deal, but OptiNAND can improve performance in some cases, although, in general, it is utilized to allow for higher-capacity drives. The Red Pro is probably the most attractive all-around drive at this time for 22TB, even if it’s rated for a lower sustained transfer rate than Seagate’s drives.

The Gold has many similarities to the Purple Pro and Red Pro, being an enterprise-class drive. It’s specifically designed to be used in multi-drive environments with performance tuning for RAID and random IOPS. It has the performance benefits of OptiNAND, too, but additionally can offer gains with Armor Cache, which is especially useful in scenarios where the write cache is disabled for data integrity. This gives it additional flexibility and reliability in any place where a power loss event is a serious concern.

All of this makes it hard to recommend for your everyday consumer system, although if you are an enthusiast with a serious home lab it might be worth consideration. Some workloads can benefit from OptiNAND or ArmorCache, and the extra reliability is nice. However, you really want to use this in mission-critical setups with many drives where storage density is also an important factor. This could include small- to medium-sized, growing businesses, although only if you need the comfort of ArmorCache over the 22TB Red Pro.

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MORE: How We Test HDDs And SSDs

MORE: Best Hard Drives


MORE: How We Test HDDs And SSDs

MORE: Best Hard Drives


MORE: How We Test HDDs And SSDs

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