Grand Theft Auto V (PC) - Athlon X4 880k - Zotac GTX 1050 Ti Very High Settings

Everything on very high except post fx and grass which are set to high (these two I believe have the most impact on FPS). Performance in beginning is fine however, once we're open up to the city 13:20, Cpu is bottle-necking the gpu. system specs CPU: AMD Athlon X4 880k 4.0 ghz stock Gpu: Zotac 1050 TI mini 4GB GDDR5(no overclocking, stock settings) Ram: 8gb Kingston hyper x ddr3 1866mhz(single channel) OS: Windows 10 Home(64 bit) Motherboard:Gigabyte GA-F2A88XM-D3HP PSU: EVGA 600w 80 white plus