Synology NAS Still Blocks Third-Party SSD Caching Despite Restoring Hard Drive Support

Synology NAS, SSD caching, DSM 7.4, third-party SSD, and NAS storage are once again making headlines when customers discovered that Synology continues to block one critical feature on its latest NAS devices. While the company has dropped its previous restrictions on third-party hard drives, users cannot use non-Synology SSDs for SSD caching on new NAS devices.

Earlier this year, Synology received criticism for requiring users of its 2026 NAS models to use only Synology-branded drives during the initial setup. This meant that users using Seagate or Western Digital hard drives couldn't install the operating system as effortlessly. After receiving feedback from the NAS community, Synology changed its policy through DSM updates, allowing users to install and use third-party hard drives again.

However, one significant limitation remains. Users can use third-party M.2 NVMe SSDs as storage devices, but not for SSD caching. This feature is still limited to Synology-branded SSDs in latest version of DiskStation Manager (DSM 7.4).

SSD caching enhances NAS speed by storing frequently accessed data on faster SSDs. This allows files and applications to load faster, especially when multiple users are using the NAS at the same time. SSD caching, which continually reads and writes data, might wear out SSDs faster than conventional storage use.

Synology claims the restriction is intended to increase reliability and eliminate support concerns. The company claims that NAS-rated SSDs are more suited for intensive workloads than standard consumer SSDs. If users install SSDs that are not designed for continuous caching, they may wear out faster or cause performance issues. Many experienced NAS users, however, believe they should be able to choose their own hardware. They claim that certain third-party SSDs are intended for business or NAS use and can readily handle caching demands.

Some experts suggested a simple approach. Instead of entirely prohibiting third-party SSD caching, Synology should include a setting that allows experienced users to enable the feature after accepting a warning. This would enable experienced users to use suitable SSDs when making.

For now, users buying a new Synology NAS should know that while third-party hard drives are once again supported, SSD caching remains limited to Synology's own SSDs. Anyone planning to use cache acceleration should check hardware compatibility before purchasing a new NAS system.

This article is based on information from XDA Developers