Which system should i go for?

[EmilXI]

I am having to choose against a used computer for 800$ and a brand new self built computer for 1000$.

800$:
I7 5820k
R9 390x 8gb
Crucial m.2 ssd 500gb
Nzxt kraken X61
Evga supernova G2 1000w
Msi x99a gaming 7
16gb vengeance ddr4 3000mhz
Nzxt source s340 elite

1000$ brand new:
Ryzen 1600
Rx 580 sspphire nitro+
16gb 3200mhz vengeance ddr4
1TB barracuda HDD
Seasonic S2II 520w
Gigabyte ga ab350
Phanteks eclipse p400s tempered glass.

Ive always wanted to build my own pc so i dont like buying a used but if it is much better (the used one) i will buy that one instead

 

[Chugalug_]

Do a self built, you can do way better in terms of performance, used are generally hit and miss and without warranty.
You don't know how people have abused their parts or if they've fried anything.

 

[Chugalug_]

Here's a good list for 1080p.
PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i7-7700 3.6GHz Quad-Core Processor ($294.98 @ NCIX US)
Motherboard: Gigabyte - GA-B250M-Gaming 3 Micro ATX LGA1151 Motherboard ($69.98 @ Newegg)
Memory: Team - Dark 16GB (2 x 8GB) DDR4-2400 Memory ($94.99 @ Newegg)
Storage: Sandisk - SSD PLUS 240GB 2.5" Solid State Drive ($77.95 @ Amazon)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($48.88 @ OutletPC)
Video Card: Zotac - GeForce GTX 1070 8GB Mini Video Card ($329.99 @ Newegg)
Case: Corsair - Carbide Series 88R MicroATX Mid Tower Case ($49.99 @ Corsair)
Power Supply: SeaSonic - S12II 520W 80+ Bronze Certified ATX Power Supply ($44.89 @ Newegg)
Total: $1011.65
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-05-15 02:39 EDT-0400

 

[Chugalug_]

Alternative.
PCPartPicker part list / Price breakdown by merchant

CPU: AMD - Ryzen 5 1500X 3.5GHz Quad-Core Processor ($188.98 @ NCIX US)
Motherboard: MSI - B350 PC MATE ATX AM4 Motherboard ($84.49 @ SuperBiiz)
Memory: Team - Dark 16GB (2 x 8GB) DDR4-2400 Memory ($94.99 @ Newegg)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($48.88 @ OutletPC)
Video Card: EVGA - GeForce GTX 1080 8GB Superclocked Gaming ACX 3.0 Video Card ($489.99 @ Newegg)
Case: Corsair - SPEC-01 RED ATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: SeaSonic - S12II 520W 80+ Bronze Certified ATX Power Supply ($44.89 @ Newegg)
Total: $992.21
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-05-15 02:41 EDT-0400