No, photoshop is not heavily optimized for heavy threading. Most actions within photoshop rely on a few strong cores so an i5 would work well. A gtx 970 is overkill.
Granted this is for cs6 but things haven't changed that much in photoshop. What's important to see here is the little difference between gpu's. Only a few actions are gpgpu accelerated.
https://www.pugetsystems.com/labs/articles/Adobe-Photoshop-CS6-GPU-Acceleration-161/
https://www.pugetsystems.com/labs/articles/Adobe-Photoshop-CC-Multi-Core-Performance-625/
The 4690k and 4770 are the same speed, hyper threading being the difference yet they perform within 2-3 seconds of each other. Meaning the hyperthreading of an i7 doesn't have much impact here other than higher cost.
http://www.tomshardware.com/charts/cpu-charts-2015/-29-Adobe-Photoshop-CC,3720.html
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i5-6500 3.2GHz Quad-Core Processor ($199.98 @ OutletPC)
Motherboard: Gigabyte GA-H170-D3HP ATX LGA1151 Motherboard ($108.99 @ SuperBiiz)
Memory: Corsair Vengeance LPX 16GB (2 x 8GB) DDR4-2400 Memory ($74.99 @ Amazon)
Storage: Patriot Blaze 60GB 2.5" Solid State Drive ($36.98 @ Mac Mall)
Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($87.89 @ OutletPC)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($48.99 @ NCIX US)
Video Card: EVGA GeForce GTX 950 2GB Superclocked+ ACX 2.0 Video Card ($129.99 @ Newegg)
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX Power Supply ($55.99 @ SuperBiiz)
Total: $743.80
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-01-21 15:49 EST-0500
Something like this build offers budget to add additional ram though 16gb is a decent amount for photoshop. When 16gb begins to fill up a bit is when using photoshop and illustrator side by side with bridge open, for that 32gb may be slightly better. It offers a strong cpu, plenty of gpu horsepower for the few things that use it, an ssd for the os and programs, smaller ssd for use as a scratch disk, 1tb hdd for bulk file storage. No real need for an additional cpu cooler, the stock cooler should work fine.