https://www.synology.com/en-global/products/DS1821+

Memory
CPU	CPU Model	AMD Ryzen V1500B
	CPU Architecture	64-bit
	CPU Frequency	4-core 2.2 GHz
	Hardware Encryption Engine (AES-NI)
Memory	System Memory	4 GB DDR4 ECC SODIMM
	Memory Module Pre-installed	4 GB (4 GB x 1)
	Total Memory Slots	2
	Maximum Memory Capacity	32 GB (16 GB x 2)
	Notes	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. Synology reserves the right to replace memory modules with the same or higher frequency based on supplier's product life cycle status. Rest assured that the compatibility and stability have been strictly verified with the same benchmark to ensure identical performance.
Storage
Storage	Drive Bays	8
	Maximum Drive Bays with Expansion Unit	18 (DX517 x 2)
	M.2 Drive Slots	2 (NVMe)
	Compatible Drive Type* (See all supported drives)	3.5" SATA HDD 2.5" SATA HDD 2.5" SATA SSD M.2 2280 NVMe SSD
	Maximum Single Volume Size*	108 TB
	Hot Swappable Drive
	Notes	"Compatible drive type" indicates drives that have been tested to be compatible with Synology products. This term does not indicate the maximum connection speed of each drive bay. Each internal volume (may consist of multiple drives) is expandable up to 108TB.
External Ports
External Ports	RJ-45 1GbE LAN Port	4 (with Link Aggregation / Failover support)
	USB 3.0 Port	4
	eSATA Port	2
PCIe
PCIe	PCIe Expansion	1 x Gen3 x8 slot (x4 link)
File System
File System	Internal Drives	Btrfs EXT4
	External Drives	Btrfs EXT4 EXT3 FAT NTFS HFS+ exFAT*
	Notes	exFAT Access is purchased separately in Package Center.
Appearance
Appearance	Size (Height x Width x Depth)	166 mm x 343 mm x 243 mm
	Weight	6 kg
Others
Others	System Fan	120 mm x 120 mm x 2 pcs
	Fan Speed Mode	Full-Speed Mode Cool Mode Quiet Mode
	Easy Replacement System Fan
	Brightness Adjustable Front LED Indicators
	Power Recovery
	Noise Level*	22.2 dB(A)
	Scheduled Power On / Off
	Wake on LAN / WAN
	Power Supply Unit / Adapter	250 W
	AC Input Power Voltage	100 V to 240 V AC
	Power Frequency	50/60 Hz, Single Phase
	Power Consumption*	59.8 W (Access) 26.18 W (HDD Hibernation)
	British Thermal Unit	204.05 BTU/hr (Access) 89.33 BTU/hr (HDD Hibernation)
	Notes	Power consumption is measured when it is fully loaded with Western Digital 1TB WD10EFRX hard drive(s). Noise Level Testing Environment: Fully loaded with Seagate 2TB ST2000VN000 hard drive(s) in the idle state. Two G.R.A.S. Type 40AE microphones, each set up 1 meter away from the Synology NAS at the front and rear. Background noise: 16.49-17.51 dB(A); Temperature: 24.25-25.75?C; Humidity: 58.2-61.8%
Temperature
Temperature	Operating Temperature	0°C to 40°C (32°F to 104°F)
	Storage Temperature	-20°C to 60°C (-5°F to 140°F)
	Relative Humidity	5% to 95% RH
Certification
Certification	FCC CE BSMI EAC CCC KC VCCI RCM
Warranty
Warranty	3-year hardware warranty
	Notes	The warranty period starts from the purchase date as stated on your purchase receipt. (Learn more)
Environment
Environment	RoHS Compliant
Packaging Content
Packaging Content	Main Unit X 1 Accessory Pack X 1 AC Power Cord X 1 RJ-45 LAN Cable X 2 Quick Installation Guide X 1
Optional Accessories
Optional Accessories	DDR4 ECC SODIMM: D4ES01-4G/D4ES01-8G/D4ECSO-2666-16G Expansion Units: DX517 2.5" SATA SSD: SAT5200 M.2 2280 NVMe SSD: SNV3400 10GbE Network Interface Card: E10G18-T2/E10G18-T1/E10G17-F2 VisualStation: VS960HD/VS360HD Surveillance Device License Pack
	Notes	All memory modules will operate at the maximum frequency specified by the CPU manufacturer.