HP Proliant SE316M1R2 Server "RAM" increase with additional slot

And also i want to upgrade the RAM, and

already existing RAM spec is

Part No : "M393B2K7CM0-CH9"

Brand: Samsung

Spec: Samsung 16GB M393B2K70CM0-CH9 PC3-10600 CL9 4Rx4 DDR3 1333MHz

Model: DRAM

Size: 16 GB

Speed: 1333MHz

Voltage: 1.5 V

Now, i want to buy the RAM with exact spec, whether shall i go with any other brand or else shall i use with existing brand.

Rajkumar