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Comparison Products
We are comparing the WD Red Pro to three other 20TB drives, including the Seagate Skyhawk AI and the Seagate Exos X20, and IronWolf Pro. Older models include the WD Black 6TB and the Seagate IronWolf Pro 8TB.
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.
You should be gaming on an SSD by now, but 3DMark still shows us that the Red Pro falls short in comparison to the competition.
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.
It’s common for drives to perform similarly in PCMark 10 and 3DMark, and that is the case here - the Red Pro is dead last again.
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 is a more valid test for HDDs than SSDs, and we see that modern HDDs perform roughly the same in transfer rate.
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.
ATTO shows us something similar to DiskBench - very predictable, comparable results for sequential performance. HDDs get very close to their theoretical maximum transfer speeds in CrystalDiskMark, as well. 4KB performance is awful compared to SSDs, but the Red Pro stands out against its 20TB competitors. This may be due to the OptiNAND technology, which would also bring big latency benefits to larger I/O in certain write cache scenarios, although for now, that is only on the 22TB WD Gold.
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.
No surprises here, with very predictable sustained write performance. Certain technologies, like Seagate’s Mach.2, can almost double the sustained transfer rate, but with notable drawbacks.
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.
HDDs are power-hungry with all of the 20TB models pulling around 8W on average.
Test Bench and Testing Notes
| CPU | Intel Core i9-12900K |
| Motherboard | Asus ROG Maximus Z790 Hero |
| Memory | 2x16GB G.Skill DDR5-5600 CL28 |
| Graphics | Intel Iris Xe UHD Graphics 770 |
| CPU Cooling | Enermax Aquafusion 240 |
| Case | Cooler Master TD500 Mesh V2 |
| Power Supply | Cooler Master V850 i Gold |
| OS Storage | Sabrent Rocket 4 Plus-G 2TB |
| Operating System | Windows 11 Pro |
Conclusion
The 20TB WD Red Pro performs as expected and checks the right boxes for a drive of this type. If you need a lot of storage for your NAS, it is a reasonable option. Pricing may vary, but you will generally pay a premium for this much storage, and the Red Pro’s price per TB is roughly comparable to the alternatives. Seagate’s Exos X20 and IronWolf Pro 20TB HDDs are direct competitors who perform very similarly for the intended workloads but may have better warranty and support options.
All of these drives use CMR technology without the drawbacks of SMR, but they arrive at these high capacities in different ways. WD’s unique approach uses NAND flash to offload metadata, which can improve performance and endurance and opens the door to other features. Right now, and for this drive, though, it should be treated as equivalent to the other options. Pricing is probably the biggest factor, although the IronWolf Pro’s Rescue Data Recovery Services may be enticing.
Beyond the bump in 4KB performance that the Red Pro displays, it also has the advantage of a larger DRAM cache. If the price is right, this may be the selling point to you that puts the drive ahead of the competition.
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