What should I upgrade first??

[tecurlee]

I am building towards getting a 34in Curved monitor with 1440p and 144hz when they become readily available.  I am planning to upgrade my PC in order to get all that I can out of the monitor when I purchase it.  What should I start upgrading first?  Also what can I keep?

 

CPU: Intel - Core i5-4690K 3.5 GHz Quad-Core Processor
Motherboard: MSI - Z97-GAMING 5 ATX LGA1150 Motherboard  
Memory: Kingston - HyperX Fury Black 8 GB (2 x 4 GB) DDR3-1866 Memory  
Storage: Samsung - 850 EVO-Series 250 GB 2.5" Solid State Drive  
Storage: Western Digital - Caviar Blue 1 TB 3.5" 7200RPM Internal Hard Drive  
Video Card: MSI - GeForce GTX 970 4 GB Twin Frozr V Video Card 
Case: Antec - Nine Hundred ATX Mid Tower Case  
Power Supply: EVGA - SuperNOVA GS 550 W 80+ Gold Certified Fully-Modular ATX Power Supply  
Optical Drive: Asus - DRW-24B1ST/BLK/B/AS DVD/CD Writer  
Operating System: Microsoft - Windows 10 Home OEM 64-bit   
Monitor: Acer - G236HLBbd 23.0" 1920x1080 60 Hz Monitor  
Monitor: Asus - VG278HV 27.0" 1920x1080 144 Hz Monitor 
Keyboard: Logitech - K350 Wireless Ergonomic Keyboard  
Mouse: Logitech - M510 Wireless Laser Mouse   
Speakers: Logitech - Z323 30 W 2.1ch Speakers  

[Slottr]

Look for a used 4790k and maybe a 1080/2070/2080

[LukeSavenije]

I would change the gpu first. Something like a 1070 ti will do you great. A 4770k or 4790k wouldn't be a bad addition too. And so it is for another 8 gigs, but that depends on your budget