https://pcpartpicker.com/list/8NyLw6 here is an AMD ryzen 3 2600 6 core 12 threaded cpu, 16gb of ddr4 3000mhz, and b450mobo for under $400. You could get 8gb of simmilar ram and save a buck.
Here is a more powerfull 8 core 16 threaded build. It is more powerfull than both of the intel builds, having 12 more threads than either i5 cpu.https://pcpartpicker.com/list/XQ3p8Y
The only thing I have now is the case, and I've been back and forth over, do I go with what Puget recommend Intel over Ryzen, or do I go with Ryzen and save $$. As long as it works good and I can get it to post.
Ryzen offers more processing cores and simmilar performance to intel for less money. A complete system for 600 will not be able to have the cpus listed above. Is your case full atx?
https://pcpartpicker.com/list/ZVpjkd here is the absolute best value for money system i could build for under $600. It features an AMD ryzen 7 1700 8 core 16 threaded processor. It also has a gigabyte b350 overclocking motherboard, 16gb 3000mhz ddr4, 240 gb kingston ssd, 8gb rx 580 video card, and 550 watt semi modular psu.