6GB is a better card and your PC can handle it.  here are 14 users benchmark of the same config.
Hi, I have the Dell Inspiron 5675, Ryzen 3 1200 processor and RX 560 2gb GPU  I want to upgrade to the GTX 1060 but don't know if I should get the 3 GB or 6 GB version I need help choosing I have a bigger budget but don't know if my pc will handle the 6 GB version
Dell Inspiron 5675, Ryzen 3 1200 GPU upgrade