---
title: Synology RS4021xs+ RackStation 16-bay NAS Storage
date: 2026-03-18T21:49:07Z
modified: 2026-05-16T14:37:53Z
permalink: "https://tech.co.za/product/synology-rs4021xs-rackstation-16-bay-nas-storage/"
type: product
status: publish
excerpt: NAS/storage server Rack (3U) Intel® Xeon® D-1541 16 GB DDR4 Black
wpid: 574756
product_brand:
  - Synology
product_type:
  - simple
product_cat:
  - Data Storage
featured_image: "https://tech.co.za/wp-content/uploads/2026/03/rs4021xsa.png"
featured_image_alt: rackstation 16 bay (up to 40 bay); octa core 2.1 ghz; 16gb ddr4 ecc udimm ram (up to 64gb); 4x gbe lan; 2x10gbe lan; 2x usb3.2
---

| **CPU** |  |
| --- | --- |
| CPU Model | Intel Xeon D-1541 |
| CPU Quantity | 1 |
| CPU Cores | 8 |
| CPU Threads | 16 |
| CPU Architecture | 64-bit |
| CPU Frequency | 2.1 (base) / 2.7 (turbo) GHz |
| Hardware Encryption Engine | Yes |
| **Memory** |  |
| System Memory | 16 GB DDR4 ECC UDIMM |
| Memory Module Pre-installed | 16 GB (16 GB × 1) |
| Total Memory Slots | 4 |
| Maximum Memory Capacity | 64 GB (16 GB x 4) |
| Notes | Synology may revise pre-installed memory module specifications in response to component lifecycle and supply conditions. All revised components undergo the same rigorous validation to ensure equivalent compatibility, stability, and performance. Please select Synology memory modules for optimum compatibility and reliability. Synology will not provide complete product warranty or technical support if non-Synology memory modules are used for memory expansion. For multi-module memory configurations, all modules must be identical and share the same model number. Check the [Product Manual](https://kb.synology.com/search?sources%5B%5D=hardware_installation_guide) of your Synology product for recommended memory configurations. |
| **Storage** |  |
| Drive Bays | 16 |
| Maximum Drive Bays with Expansion Unit | 40 (RX1217 × 2) |
| Drive Type [(See all supported drives)](https://www.synology.com/en-us/compatibility?search_by=drives) | 3.5″ SATA HDD 2.5″ SATA SSD |
| Hot Swappable Drive\* | Yes |
| Notes | Synology only guarantees full functionality, reliability, and performance for Synology drives listed on the [compatibility list](https://www.synology.com/en-us/compatibility). The use of non-validated components may limit certain functionality and result in data loss and system instability. |
| **External Ports** |  |
| RJ-45 1GbE LAN Port | 4 |
| RJ-45 10GbE LAN Port | 2 |
| USB 3.2 Gen 1 Port | 2 |
| Expansion Port | 2 |
| Expansion Port Type | Infiniband |
| More info: | [https://www.synology.com/en-us/products/RS4021xs+#specs](https://www.synology.com/en-us/products/RS4021xs+#specs) |