5yr old computer, what should I upgrade first? Mobo+CPU+RAM or GPU?

[sendtomikaela]

I bought this PC second-hand for €485 and I upgraded the PSU, CPU Cooler, added fans, RGB LED cables, bought a new case and an SSD. It's 5yrs old now.

I am planning to upgrade, but I don't know which parts to buy first. I want a GTX 1080, 7700K, DDR4 3000MHz and a Z270 motherboard.

Here are my PC's current specs:
Motherboard: MSI B75A G43 Gaming Red Dragon
CPU: i7-2600K 3.4GHz
RAM: 4x4 16GB DDR3 1886MHz
GPU: Nvidia GTX 780 Reference Card

 

[vapour]

GPU is a close to GTX 1060, still very capable at 1080p level. 2600k is still fine for 1080p 60hz gaming, but if you want to upgrade, CPU first.

If only gaming, I5-8500, B/H/Z 3xx MB and 8gb ddr4 ram depending on your budget.

Do you overclock? If so, I5-8600k is better with Z370 MB. GTX 1080 is better with 1440p 144hz monitor.