The 16-bay RS4021xs+ provides solid data security and lightening-fast performance with over 234K 4K random read IOPS and 6,258 MB/s sequential read throughput1. Together with its 8-core processor, ECC memory, advanced snapshot technology, and built-in 10GbE connectivity, the RS4021xs+ can support large multi-user environments while handling data-intensive workloads. CPU Model Intel Xeon D-1541 CPU Architecture 64-bit CPU Frequency 8-core 2.1 (base) / 2.7 (turbo) GHz Hardware Encryption Engine (AES-NI) System Memory 16 GB DDR4 ECC UDIMM Total Memory Slots 4 Maximum Memory Capacity 64 GB (16 GB x 4) Maximum Drive Bays with Expansion Unit 40 (RX1217/RX1217RP x 2) Hot Swappable Drive RJ-45 1GbE LAN Port 4 (with Link Aggregation / Failover support) RJ-45 10GbE LAN Port 2 (with Link Aggregation / Failover support) USB 3.2 Gen 1 Port* 2 PCIe Expansion 2 x Gen3 x8 slots (x8 link) Form Factor (RU) 3U Rack Installation Support* 4-post 19' rack (Synology Rail Kit - RKS1317) not included System Fan 80 mm x 80 mm x 3 pcs Mention: If NAS use over 8TB HDD, please only chose Synolgy Brand HDD https://www.synology.com/en-global/compatibility