How do I install an SSD into my Synology NAS for the best SSD cache performance?

Due to the specification limits of the SATA controllers used in Synology DS415+, DS1515+, and DS1815+, the maximum transmission speed will vary depending on the drive bay. If you need to enable SSD cache on one of these models, please install the SSDs into Drive Bay 1 or Drive Bay 2, each with a transmission speed of SATA 6.0 Gb/s, in order to achieve optimal performance. There are no SSD installation limitations for other Synology NAS models.

If you have already created a storage volume in DS415+, DS1515+, or DS1815+ but the SSDs used as system cache are not installed in Drive Bay 1 or Drive Bay 2, please refer to the following steps to change the configuration:

  1. Do not modify any system settings. Shut down the system normally.
  2. Remove all drives from the system.
  3. Install the SSDs into Bay 1 and Bay 2, and the rest HDDs into other drive bays.
  4. Power on the system.
  5. Go to DSM > Storage Manager and confirm the status of the storage volume and SSD cache settings.