Could someone put together a gaming PC with the fastest possible hardware you can get for around $1,200?

https://pcpartpicker.com/list/JmkZQZ

"gaming PC" is a little general. A GTX 1060 6GB will be fine for 1080p. I threw in a 1070Ti for the potential to get decent gaming settings at 1440p. Threw in a 1700x to get the most from the card. 16GB RAM obviously. M.2 SSD for boot. Decent-sized 2nd SSD (you might want a 2TB or 4TB HDD instead). Motherboard was selected to keep budget down. Gold / semi PSU to keep quality good, and budget down a little.

Still need:

Operating system
Monitor(s)
Input devices
Optical drive(s), if applicable
Case to suit all of the above

If gaming at 1080p, drop to a GTX 1060 6GB, and a Ryzen 5 1600x at the most (a 1600 should suffice).
 
would you use used parts? you can get 2x stronger hardware for the same price if you are willing to buy some used components, mainly processors that weren't overclocked
 
What monitor will you be using? This will impact your build. This build will be ideal for a 1440p 144hz monitor.

PCPartPicker part list: https://pcpartpicker.com/list/CH2Dw6
Price breakdown by merchant: https://pcpartpicker.com/list/CH2Dw6/by_merchant/

CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor ($178.99 @ Amazon)
Motherboard: Gigabyte - B360M DS3H Micro ATX LGA1151 Motherboard ($68.09 @ Amazon)
Memory: Crucial - Ballistix Sport LT 16GB (2 x 8GB) DDR4-2666 Memory ($159.99 @ B&H)
Storage: Crucial - MX500 1TB 2.5" Solid State Drive ($199.89 @ OutletPC)
Video Card: Gigabyte - GeForce GTX 1080 8GB WINDFORCE OC 8G Video Card ($504.98 @ Newegg)
Case: Phanteks - ECLIPSE P400 TEMPERED GLASS ATX Mid Tower Case ($64.99 @ Newegg)
Power Supply: Corsair - TXM Gold 650W 80+ Gold Certified Semi-Modular ATX Power Supply ($59.99 @ Newegg)
Total: $1236.92
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-26 08:14 EDT-0400
 
You may want to specify if you also need a monitor or peripherals as that's going to change the build drastically.


Tower Only

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor ($178.99 @ Amazon)
Motherboard: ASRock - H310M-HDV/M.2 Micro ATX LGA1151 Motherboard ($59.89 @ SuperBiiz)
Memory: ADATA - XPG GAMMIX D10 16GB (2 x 8GB) DDR4-2666 Memory ($159.99 @ Amazon)
Storage: Crucial - MX500 500GB M.2-2280 Solid State Drive ($109.89 @ OutletPC)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($43.90 @ OutletPC)
Video Card: MSI - GeForce GTX 1070 Ti 8GB Video Card ($459.99 @ B&H)
Case: Fractal Design - Focus G (Black) ATX Mid Tower Case ($44.99 @ SuperBiiz)
Power Supply: Corsair - TXM Gold 550W 80+ Gold Certified Semi-Modular ATX Power Supply ($39.99 @ Newegg)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($95.89 @ OutletPC)
Total: $1193.52
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-26 08:25 EDT-0400

Full Build

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor ($178.99 @ Amazon)
Motherboard: ASRock - H310M-HDV/M.2 Micro ATX LGA1151 Motherboard ($59.89 @ SuperBiiz)
Memory: ADATA - XPG GAMMIX D10 8GB (2 x 4GB) DDR4-2666 Memory ($93.98 @ Newegg)
Storage: Crucial - MX500 250GB M.2-2280 Solid State Drive ($69.85 @ OutletPC)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($43.90 @ OutletPC)
Video Card: Gigabyte - GeForce GTX 1060 6GB 6GB WINDFORCE OC 6G Video Card ($279.99 @ Newegg)
Case: Fractal Design - Focus G (Black) ATX Mid Tower Case ($44.99 @ SuperBiiz)
Power Supply: Corsair - TXM Gold 550W 80+ Gold Certified Semi-Modular ATX Power Supply ($39.99 @ Newegg)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($95.89 @ OutletPC)
Monitor: Acer - GN246HL 24.0" 1920x1080 144Hz Monitor ($194.62 @ B&H)
Keyboard: Corsair - K55 RGB Wired Gaming Keyboard ($47.99 @ Amazon)
Mouse: Corsair - M65 PRO RGB FPS Wired Optical Mouse ($39.99 @ Amazon)
Headphones: Logitech - G430 7.1 Channel Headset ($39.99 @ Best Buy)
Total: $1230.06
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-26 08:28 EDT-0400