It's the motherboard that determines "dual channel", not the memory itself.
Here is the HP memory page for your particular model. Get stuff that matches these specs: HP Pavilion p6617c Desktop PC Product Specifications HP Pavilion p6617c Desktop PC - HP Customer Care (United States - English)
Dual channel memory architecture
Four DDR3 DIMMs (240-pin) sockets
Non-ECC memory only, unbuffered
Supports 1GB, 2GB, and 4GB DDR3 DIMMs
Supports up to 16 GB on 64-bit systems
Supports up to 4 GB on 32-bit PCs
*32-bit PCs cannot address a full 4.0 GB of memory.