DDR2
From Amazon
MicroMemory 8GB DDR2 – 800 MHz PC2-6400 2 x 4 GB DIMM Memory Module Option Kit, 504351 504589 001 (2 x 4GB DIMM Modules)
Compadvance
COREPARTS 8Gb Memory Module For Hp 800Mhz
Athema Services
micromemory 8gb ddr2 800mhz pc2-6400 2x4gb dimm memory module mmxhp-dd