Features:
512MB Synchronous dual in-line memory module (DIMM) DRAM for Cisco 2821 Router
The Cisco 2821 Router has a default memory configuration of 128 MB of removable Compact Flash and 512 MB of synchronous dynamic RAM (SDRAM) memory.
The maximum memory supported on the Cisco 2821 is 256MB Compact Flash and 1GB of Synchronous dual in-line memory module (DIMM) DRAM.