This HP 731761-S21 compatible 8GB DDR3-1866MHz Single Rank Registered ECC 1.5V 240-pin CL13 factory original RDIMM is 100% guaranteed to be compatible with your system and to work right the first time. Adding additional memory is the best way to increase the performance of your system. All our memory is built to strict JEDEC standards to meet or exceed the Tier 1 OEM's factory requirements. Our products are also guaranteed by federal law to not affect or void OEM warranties.

• DIMM 8 GB of memory makes a perfect symmetry with your latest model processor and boosts up your computer's performance
• DDR3 SDRAM interface multiplexes 2-bit data from memory cell and I/O buses to minimize processor idle time and enhance your computer's performance
• No matter how heavy and numerous the applications that you are using, 1866 MHz memory speed with Registered signal will run them smoothly