Best Hard Drives for Synology DS420+ NAS in 2020

Seagate IronWolf is a series from the company for NAS installations, rivaling Western Digital's Red. Packing similar technology, named AgileArray, which offers enhanced performance and reliability over traditional desktop-class hard drives. These drives can be installed in a configuration of up to eight. If you need a little more performance still or wish to fill up a NAS with more than eight bays, you'll need the IronWolf Pro.

Western Digital's (WD) Red family of hard drives are manufactured for NAS use, and like Seagate's IronWolf can be deployed in systems that support up to eight bays. Known as a powerful brand in the storage market, WD drives are top quality, and they last a long time. The Red series isn't the fastest batch of hard drives on the market, but using them in a RAID formation can make up for this.

HGST is part of Western Digital, so you can expect similar performance, reliability, and customer service experience as you would with the parent company. Vibration protection and a million hours MTBF (mean time before failure) make these NAS-classified drives ideal for deployment at home or in a small office. These drives are relatively expensive, but you get better speed than WD Red and Seagate's IronWolf.

Seagate has the IronWolf Pro available for NAS owners who need more performance with faster 7,200 RPM motors and up to 250MB/s of sustained data transfer. There's also a 300TB per year workload limit. These are heavy-duty storage devices for a NAS that can go into units with up to 24 bays.

Just like Seagate, Western Digital has a "pro" series of drives, which are even more capable than the standard lineup of NAS storage options. Supporting up to 24 bays, these drives come with more advantage features, including 3D Active Balance Plus and error recovery controls.

Seagate's IronWolf SSD range takes everything that makes the IronWolf HHDs so good and turns it all up to 11. That's because these are solid-state drives and not mechanical hard drives. That means no motors and moving parts. These drives start from 240GB with a 560MB/s sustained transfer speed for enhanced performance compared to mechanical drives.

Like the IronWolf SSD series from Seagate, the Red SSD family of drives offer improved transfer rates compared to normal NAS HDDs. The price hike can be justified by the performance bump alone, not to mention lower power draw and no mechanical moving parts.

If your NAS has an M.2 slot for a rapid SSD like the Samsung EVO Plus, you should consider buying one. These aren't technically used for expanding the capacity of your NAS per se but instead are used to store frequently accessed files. M.2 NVMe drives are considerably faster than SATA hard drives and SSDs, making this ideal for a NAS with multiple users.