Lazarus, welcome to Tom's Hardware Forums!
Here are the specs of the RAM in your computer:
Max RAM Supported 8 GB - Technology DDR3 SDRAM - Speed 1066 MHz / PC3-8500 - Form Factor SO DIMM 204-pin - Slots Qty 2
What you have selected is DDR3-1600/PC3-12800 - Your motherboard supports DDR3 1066 MHz / PC3-8500 RAM and will downclock the higher frequency RAM. You will not gain anything. There is also the possibility that the higher speed RAM may create problems.
My suggestion is to leave the existing 4 GBs RAM alone.