WD Red SA500 NAS SSD Review: Excellent for PCs, Too!

Dong Ngo | Dong Knows Tech The WD Red SA500 SSD is available in standard 2.5-inch and M.2 form factors.

The WD Red SA500 SSD is Western Digital’s formidable contender to Seagate’s IronWolf 110. The new NAS-centric solid-state drive proved to be faster than its rival in my testing. Most importantly, it costs significantly less, just around 15 cents per gigabyte compared to some 25 cents of the Seagate. And it’s also more versatile, available in both 2.5-inch and M.2 form factors.

The new WD Red SSD isn’t perfect, though, since it has a significantly lower endurance rating than the Seagate counterpart. But that’s just a minor shortcoming. If you’re looking for a reliable SSD to use inside your NAS, or as a replacement drive for your computer, the WD Red SA500 is an excellent choice.










  • Affordable with long warranty
  • Excellent performance
  • 2.5-inch and M.2 form factors
  • High capacity


  • Relatively low endurance when compared to competing drive
  • No NVMe version, 2.5-inch to 3.5-inch mounting bracket not included

WD Red SA500: A versatile standard SSD

As mentioned above, the WD Red SA500 comes in two flavors. It’s available in up to 4TB in standard 7mm 2.5-inch (laptop) form factor, and up to 2TB in the newer M.2 2280 design.

If you’re not sure which is which, I talked about them in detail in this post. It’s important to note that the M.2 version doesn’t support the NVMe interface. It remains a SATA drive.

The 2.5-inch design is a perfect fit for mini NAS servers, like the Synology DS620slim, or the DS419slim, and the M.2 can work right away as a cache for the DS1019+, though, in this case, I wish it were an NVMe drive. Of course, you can use an adapter (not included) to use the SA500 in any server of any physical sizes. And both drives will also work with any standard computer that supports their interfaces.

The SA500 uses SATA 3, which caps at 6Gbps. Considering most NAS servers’ performance is limited by their network connection, which generally caps at 1Gbps, the SA500 is more than fast enough.

Dong Ngo | Dong Knows Tech With up to 4TB of storage space, the new WD Red SA500 SSD is perfect for a high-end NAS server.

Comparatively low endurance

Endurance is the amount of data you can write to an SSD before you can’t anymore. The higher the rating is, the more writes you can perform on a drive. We measure endurance by the number of terabytes that can be written (TBW). A higher-capacity drive of the same model generally has higher TBW.

The Seagate’s IronWolf 110 has the highest endurance I’ve seen in a standard SSD. Its 480GB capacity, for example, can handle 875 TBW. For comparison, the 500GB WD Red SA500 can take only 350 TBW, less than half. While that sounds like a big gap because it is. And endurance is necessary since NAS servers are designed to work 24/7 with lots and lots of transactions.

But keep in mind that 350TB is already a massive amount of data. If you write 50GB — about two Blueray movies worth of data — to a 500GB WD Red per day and every day, it’ll still take you some 20 years to wear it out. The 1TB and 2TB versions will take you 40 and 80 years, respectively.

In fact, the SA500’s endurance easily beats that of most conventional SSDS. The 480GB Crucial BX500 that came out earlier this year, for example, has an endurance rating of just 120 TBW. Even the more venerable Samsung 860 Evo‘s 500GB version has a lower endurance rating of 300 TBW.

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So, higher endurance is always better. But, at some point, it doesn’t matter much anymore because you will likely need to replace or decommission the drive for other reasons before it runs out of writes. What’s important is the warranty which the WD Red SA500 shares with the Seagate IronWolf 110 — both have a five-year.

WD Red SA500’s specifications

Being NAS-specific only means that the SA500 has a higher endurance and better equipped to deal with 24/7 applications, compared with traditional SSDs. In return, the drive might not have features turned for standard usages, such as lower power usage or built-in hardware encryption.

On this matter, WD told me that while the SA500 is “geared for the additional writes/reads” in 24/7 NAS operations. it will work fine for any standard PC setup.

WD Red SA500: Impressive performance

Western Digital provided me with four 2TB SA500 drives — two of each form factor — for testing, and they all did very well.

Great for standard PCs

I first tested them as a replacement drive for a conventional computer. The 2.5-inch drive fitted any applications in which I used a regular SATA hard drive, and the M.2, which has both E- and B- key, worked well with my test desktop. It will work with almost all desktop computers via a PCIe adapter card, by the way.

Dong Ngo | Dong Knows Tech

As for performance, the SA500 was impressive. In the sequential (copy) test, it averaged almost 500 MB/s and more than 525 MB/s for writing and reading, respectively. When I made it do both reading and writing at the same time, the drive still registred 250 MB/s. What’s most noteworthy is the fact it beat the Seagate IronWolf in all of these tests, albeit only by a small margin.

I tested the WD Red SA500 with lots of data (almost 600 GB) at a time to see if performance would be consistent throughout, and it was.

Excellent for NAS servers

In the random access tests, the WD Red SA500 topped the chart in writing. For writing, it was right in the middle, but still significantly faster than the Seagate IronWolf 110. Fast random access speeds will translate into fast database access, application launching, and speedy executions of online transactional processing (OLTP) tasks.

In other words, the WD Red SA500 will work well for its intended role of a NAS SSD. And it did in my real-world anecdotal tests.

Dong Ngo | Dong Knows Tech

Like the case of the Seagate drive, I tried the WD Red SA500 with a couple of Synology NAS servers, including the DS620slim and the DS410slim.

It’s important to note these servers (as well as most existing home and business NAS boxes) hook to a network via a Gigabit connection. As a result, 1Gbps is their top data throughput speed.

Since hard drives are already much faster than that, upgrading these servers’ storage to SSD won’t improve their connection speed much, if at all. If you want to see higher connection speeds, you’ll need to get a server with a multi-gig network port and use it with a multi-gig router or switch.

Dong Ngo | Dong Knows Tech You need at least two WD Red NAS SSDs of the same form factor to use them in a RAID setup.

But all servers will benefit from the WD Red SA500 drive, just in different ways.

For example, for testing, I used two drives in a RAID 1 volume on the DS620slim. I then used that volume to host a Windows Server 2016 virtual machine. Via a remote desktop connection, the VM felt just like it was a real machine.

On top of that, the NAS server itself also booted a lot faster, and its applications now launched instantly.

Comparatively, the Seagate IronWolf 110 SSD delivered about the same experience but at a much higher cost. By the way, the WD Red NAS drive was cooler to the hand than the Seagate counterpart in extended operations. 


Fast, spacious, and, most importantly, affordable, the new NAS-centric WD Red SA500 is an excellent SSD option. If you have rare NAS applications that require extreme endurance, the Seagate IronWolf 110 might a better fit. Otherwise, a couple of WD Red SA500 drives will give you a killer NAS setup at a much friendlier cost.

Don’t have a server? The WD Red SA500 is also an excellent SSD upgrade for any desktop computer. Get one, and you won’t be disappointed.

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