Upgrade CPU or GPU First?

BenWVU

Distinguished
Apr 6, 2014
30
0
18,540
Approximate Purchase Date: Immediately - End of 2018

Budget Range: $800

System Usage from Most to Least Important: Gaming (mostly FPS, some strategy)

Are you buying a monitor: No
I have this one, currently.
Dell - S2417DG 23.8" 2560x1440 165Hz Monitor
https://pcpartpicker.com/product/CwgPxr/dell-s2417dg-238-165hz-monitor-s2417dg

Parts to Upgrade:
Intel - Core i5-7600K 3.8GHz Quad-Core Processor
https://pcpartpicker.com/product/dQM323/intel-core-i5-7600k-38ghz-quad-core-processor-bx80677i57600k

Cooler Master - Hyper T2 54.8 CFM Sleeve Bearing CPU Cooler
https://pcpartpicker.com/product/FNXfrH/cooler-master-cpu-cooler-rrht228pkr1

Gigabyte - GeForce GTX 1070 8GB Windforce OC Video Card
https://pcpartpicker.com/product/4XyxFT/gigabyte-geforce-gtx-1070-8gb-windforce-oc-video-card-gv-n1070wf2oc-8gd

MSI - Z270 GAMING PRO CARBON ATX LGA1151 Motherboard
https://pcpartpicker.com/product/yY8H99/msi-z270-gaming-pro-carbon-atx-lga1151-motherboard-z270-gaming-pro-carbon

G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-2400 Memory
https://pcpartpicker.com/product/4vWrxr/gskill-memory-f42400c15d16gvr

Intel - 600p Series 512GB M.2-2280 Solid State Drive
https://pcpartpicker.com/product/w34NnQ/intel-600p-series-512gb-m2-2280-solid-state-drive-ssdpekkw512g7x1

EVGA - SuperNOVA GS 650W 80+ Gold Certified Fully-Modular ATX Power Supply
https://pcpartpicker.com/product/h3FXsY/evga-power-supply-220gs0650v1

Preferred Website(s) for Parts: Newegg.com, Amazon.com (This isn't a dealbreaker for me.)

Location: United States

Parts Preferences: Intel and Nvidia

Overclocking: Maybe

SLI or Crossfire: No

Your Monitor Resolution: 2560x1440

Additional Comments:
I'm considering either a GTX 1080 Ti or an RTX 2070 (after seeing benchmarks), but I' wondering if I should upgrade my CPU, first.

And Most Importantly, Why Are You Upgrading:
I seem to be pusing my CPU to it's limits in some games, such as Battlefield 1, and I want to be prepared for future games, such as Battlefield 5.
I also want to take advantage of higher framerates on my monitor (up to 144Hz) while playing with the highest graphics settings. (Right now, I can play most newer games between ~50 and ~110 fps on the highest settings.)