Hittade detta:
Memory
Standard 512-MB, 1024-MB, 2048-MB, or 4096-MB 667-MHz DDR2 SDRAM; two SODIMM slots supporting dual channel memory
Maximum Upgradeable to 4096-MB maximum (2048-MB SODIMM in slots 1 and 2)
Dual-channel Maximized dual-channel performance requires SODIMMs of the same size and speed in both memory slots.
NOTE: Due to the non-industry standard nature of some third-party memory modules, we recommend HP branded memory to ensure compatibility. If you mix memory speeds, the system will perform at the lower memory speed. Full availability of 4 GB of memory requires Windows Vista Business 64-bit or Linux. With Windows 32-bit operating systems, the amount of usable memory is dependent upon your configuration, so that above 3 GB all memory may not be available due to system resource requirements.
Genom att googla på: hp 6715b memory specs
(http://h18000.www1.hp.com/products/quickspecs/12686_na/12686_...)
Bör funka även med Pc2 6400/800MHz RAM.