Synology DiskStation DS1621+Source: Rich Edmonds / Windows Central

SSD cache is the leverage of faster solid-state storage to improve the performance of NAS-class mechanical drives. Hard drives are notoriously slower than SSDs, and by storing frequently accessed data on these drives, speeds can improve considerably. It's easy to install SSD cache on a Synology NAS, so long as you have the necessary M.2 slots or free drive bays.

What is SSD cache on Synology NAS?

Samsung 970 EVO PlusSource: Richard Devine / Windows Central

Not all Synology NAS enclosures support SSD cache, but if yours does and you have a spare drive bay or M.2 slot, you may be able to take advantage of improved system performance. Instead of accessing data from slower mechanical hard drives all the time, you can use faster SSDs (like a Samsung 970 EVO Plus) to store some of the most frequently accessed data.

To see whether your NAS supports this feature, please check to see if your enclosure is listed below.

2.5-inch SSD


  • FS3400
  • FS3600
  • FS6400
  • FS2017
  • FS3017
  • SA3400
  • SA3600
  • RS10613xs+
  • RS18016xs+
  • RS18017xs+


  • SA3200D
  • RC18015xs+


  • FS1018
  • DVA3221
  • DS1621+
  • DS1621xs+
  • DS1821+
  • RS1221+
  • RS1221RP+
  • RS2421+
  • RS2421RP+
  • RS2821RP+
  • RS3621RPxs
  • RS3621xs+
  • RS4021xs+
  • DS620slim
  • DS420+
  • DS720+
  • DS920+
  • DS1520+
  • RS820+
  • RS820RP+
  • DVA3219
  • DS1019+
  • DS1819+
  • DS2419+
  • DS2419+II
  • RS1219+
  • RS1619xs+
  • DS718+
  • DS918+
  • DS1618+
  • DS3018xs
  • RS818+
  • RS818RP+
  • RS2418+
  • RS2418RP+
  • RS2818RP+
  • RS3618xs
  • DS1517
  • DS1817
  • DS1517+
  • DS1817+
  • DS3617xs
  • DS3617xsII
  • RS3617xs
  • RS3617RPxs
  • RS3617xs+
  • RS4017xs+
  • DS716+
  • DS716+II
  • DS916+
  • RS2416+
  • RS2416RP+
  • DS715
  • DS1515
  • DS415+
  • DS1515+
  • DS1815+
  • DS2415+
  • DS2015xs
  • DS3615xs
  • RS815+
  • RS815RP+
  • RS814+
  • RS814RP+
  • RS2414+
  • RS2414RP+
  • RS3614xs
  • RS3614RPxs
  • RS3614xs+
  • DS713+
  • DS1513+
  • DS1813+
  • DS2413+
  • RS3413xs+
  • DS412+
  • DS1512+
  • DS1812+
  • DS3612xs
  • RS812+
  • RS812RP+
  • RS2212+
  • RS2212RP+
  • RS2212RP+
  • RS3412xs
  • RS3412RPxs
  • DS3611xs
  • RS3411xs
  • RS3411RPxs



  • DS1621+
  • DS1621xs+
  • DS1821+
  • DS420+
  • DS720+
  • DS920+
  • DS1520+
  • DS1019+
  • DS918+


  • RS1619xs+

M.2 SSD adapter

Should your Synology NAS have expansion slots, you may be able to use one of the available M.2 SSD adapters from Synology. Please see the official website for further details.

Even the best NAS for home can take advantage of better storage performance.

Check how much cache your Synology NAS needs

Synology has an SSD Cache Analyzer tool that can help provide some insight into how much cache would be required to see notable performance improvements. To run this wizard, follow these steps:

  1. Launch Storage Manager.
  2. Click on the storage pool you want to have analyzed.
  3. Click on SSD Cache Analyzer.
  4. Select a volume for calculation.
  5. Click Next.

The wizard will automatically begin totaling the size required, based on the size and number of recently accessed files on the selected volume.

How to set up SSD cache on Synology NAS

  1. Power down the NAS and install the SSDs into the respective slots/bays.
  2. Boot up the Synology NAS.
  3. Launch Storage Manager.
  4. Click on Storage.
  5. Click on Create > SSD Cache.
  6. Select the desired cache mode.
  7. Select the volume to which the SSD cache will be mounted.
  8. Select the SSDs from the list.

Your Synology NAS will commence using the newly added SSD cache for improving the performance of the unit by storing frequently accessed data.

Samsung 970 Evo Plus Ssd 1tb

Samsung 970 EVO Plus

Samsung's 970 EVO Plus is a rapid M.2 drive that's capable of delivering stored data at vastly faster rates compared to NAS hard drives.

Synology SAT5200 SSD

Synology SAT5200 SSD

While an SSD still cannot compete against mechanical HDDs for value and capacity, Synology's initial SSD offering with the SAT5200 is a step in the right direction. It's a must-have for your NAS if you want flash storage.

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