Ryzen 5 2600 with Rx580 will be the best choice under 800 here are the detailed parts used in this build
PCPartPicker part list:
https://pcpartpicker.com/list/MzjDTB
Price breakdown by merchant: https://pcpartpicker.com/list/MzjDTB/by_merchant/
CPU: AMD - Ryzen 5 2600 3.4 GHz 6-Core Processor ($165.98 @ Newegg)
Motherboard: *Gigabyte - B450M DS3H Micro ATX AM4 Motherboard ($74.88 @ OutletPC)
Memory: *Team - Vulcan 16 GB (2 x 8 GB) DDR4-3000 Memory ($89.89 @ OutletPC)
Storage: *Team - T-FORCE DELTA RGB 500 GB 2.5" Solid State Drive ($49.99 @ Newegg)
Storage: *Hitachi - Ultrastar 7K3000 2 TB 3.5" 7200RPM Internal Hard Drive ($50.45 @ Amazon)
Video Card: *PowerColor - Radeon RX 580 8 GB Video Card ($169.99 @ Newegg)
Case: Cooler Master - MasterBox Q300L MicroATX Mini Tower Case ($39.99 @ Amazon)
Power Supply: *Corsair - TXM Gold 550 W 80+ Gold Certified Semi-Modular ATX Power Supply ($59.87 @ OutletPC)
Total: $701.04
Prices include shipping, taxes, and discounts when available
*Lowest price parts chosen from parametric criteria
Generated by PCPartPicker 2019-01-26 15:49 EST-0500