Wow, it is expensive over there. I like the US pricing much more. lol.
On average, the 8400 give 2% fewer fps than the 8600k and less than 4% few fps than the 8700k. It is not worth the extra money for the 8600k/8700k for gaming. If you are big into overclocking, then it will make sense. The 8400 is cheaper, comes with a cooler, and a less expensive motherboard.
https://www.techpowerup.com/reviews/AMD/Ryzen_7_2700X/13.html
I would take that extra money saved and put it in some RAM or a better GPU. The 580 and the 1060 are very close in performance and the pricing has normalized. If you have a free sync monitor, then you should go with the 580.
Here is a build with the 8400, 580, and 16gb of RAM.
PCPartPicker part list:
https://au.pcpartpicker.com/list/QVdcxG
Price breakdown by merchant: https://au.pcpartpicker.com/list/QVdcxG/by_merchant/
CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor ($248.00 @ Shopping Express)
Motherboard: Gigabyte - B360M DS3H Micro ATX LGA1151 Motherboard ($90.91 @ Amazon Australia)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-2666 Memory ($256.21 @ Amazon Australia)
Storage: Crucial - MX300 275GB M.2-2280 Solid State Drive ($99.00 @ PLE Computers)
Storage: Seagate - BarraCuda 1TB 3.5" 7200RPM Internal Hard Drive ($55.00 @ Centre Com)
Video Card: Asus - Radeon RX 580 8GB DUAL Video Card ($449.00 @ PCCaseGear)
Case: Phanteks - ECLIPSE P400 TEMPERED GLASS ATX Mid Tower Case ($80.16 @ Amazon Australia)
Power Supply: Corsair - CX (2017) 550W 80+ Bronze Certified ATX Power Supply ($87.00 @ Shopping Express)
Total: $1365.28
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-11 23:51 AEST+1000
This one is a little more over budget, it has replaced the 580 with a 1070, but dropped the RAM down to 8gb. 8gb is enough for the vast majority of games and you could always get more RAM down the road.
PCPartPicker part list:
https://au.pcpartpicker.com/list/NYPNzY
Price breakdown by merchant: https://au.pcpartpicker.com/list/NYPNzY/by_merchant/
CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor ($248.00 @ Shopping Express)
Motherboard: Gigabyte - B360M DS3H Micro ATX LGA1151 Motherboard ($90.91 @ Amazon Australia)
Memory: G.Skill - Ripjaws V Series 8GB (2 x 4GB) DDR4-2666 Memory ($145.20 @ Amazon Australia)
Storage: Crucial - MX300 275GB M.2-2280 Solid State Drive ($99.00 @ PLE Computers)
Storage: Seagate - BarraCuda 1TB 3.5" 7200RPM Internal Hard Drive ($55.00 @ Centre Com)
Video Card: GALAX - GeForce GTX 1070 8GB EX Video Card ($599.00 @ Mwave Australia)
Case: Phanteks - ECLIPSE P400 TEMPERED GLASS ATX Mid Tower Case ($80.16 @ Amazon Australia)
Power Supply: Corsair - CX (2017) 550W 80+ Bronze Certified ATX Power Supply ($87.00 @ Shopping Express)
Total: $1404.27
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-11 23:52 AEST+1000