This memory module is designed for servers and is 266MHz 184 pin ECC Registered (Registers delay memory information for one clock cycle to ensure all communication from the chipset is collected by the clock edge, providing a controlled delay on heavily loaded memory within intense server applications).

General Features:
- 512MB PC2100 DDR266 Registered ECC 184pin
- 266 MHz data rate

NOTE: Your machine MUST be able to use ECC REGISTERED memory to use this