. HP 4GB (1x 4GB) Single Rank x 4 PC3-12800R (DDR3-1600) Registered CAS-11 Memory Kit Memory Size (Total) 4096MB (1 module (s) x 4096MB) Memory Type DDR3 Memory Speed 1600 M Hz Designation PC3-12800 Bus I/O Configuration Registered CAS Latency CL11 Memory Chip Features Single Rank x 4..