Hardware

5600 has more l3 cache than 5600g. 5600g has an igpu.

In terms of game performance, you'll see a very small jump in performance (3-8%) in favor of the 5600. But in fps games you'll find a benefit of 30-70%

Source: I was deciding between a 5600g and a 5600 back when I was building my current rig, so I looked through a bunch of benchmark videos. In conclusion: the difference isn't particularly noteworthy unless you're going to play fps too, in which case the 5600 is the better option.