Kingston Technology is the world?s independent memory leader and is well-known for providing high quality memory products at an attractive price. System Specific memory modules are designed and tested in the relevant systems prior to release; and they are guaranteed to be 100% compatible with your system. All Kingston System Specific memory come with a lifetime warranty. Memory clock speed: 1333 Internal memory: 4000 Internal memory type: DDR3 Memory layout: 1 x 4096 Memory voltage: 1.5 V ECC: Y Registered: Y Memory bus: 72 Lead plating: Gold Module configuration: 512M X 72 Chips organisation: X4 Compatibility: 500658-B21 (HP); 500658-S21 (HP); FX622AA (HP) Memory type: DDR3