This HP PX977AT compatible 2GB DDR2-667MHz Dual Rank Unbuffered 1.8V 240-pin CL5 UDIMM 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.

• 2 GB memory allows you to have more programs open at a time
• DDR2 SDRAM interface synchronizes electrical and clock signals for an efficient data transfer rate
• Up to 667 MHz speed with Unbuffered signal is enough to run heavy software smoothly while surfing web with dozens of tabs open