Hi dude..
The asrock n68c-gs fx and the 750 Ti are very low spec indeed.. You need to get an i3-6100 and a GTX 950 atleast.. Will cost you a little more initially but will save you a lot of trouble sinking your hard-earned money into the low-performance AM3+ amd pc..
This is a long-term solution, but if you want a low-cost short-term solution, you can just upgrade the cpu in the arock
asrock n68c-gs fx to the opteron 3300.. keep the GPU & other components, the same -- but you will have to again think about upgrading in a yr or so..
Long-term upgrade:
PCPartPicker part list:
http://pcpartpicker.com/p/KHZd8d
Price breakdown by merchant: http://pcpartpicker.com/p/KHZd8d/by_merchant/
CPU: Intel Core i3-6100 3.7GHz Dual-Core Processor ($110.99 @ SuperBiiz)
Motherboard: Asus H110M-C D3 Micro ATX LGA1151 Motherboard ($55.19 @ B&H)
Memory: Kingston HyperX Fury Black 8GB (2 x 4GB) DDR3-1600 Memory (Purchased For $0.00)
Storage: Seagate Barracuda 7200.12 500GB 3.5" 7200RPM Internal Hard Drive (Purchased For $0.00)
Video Card: Gigabyte GeForce GTX 750 Ti 2GB WINDFORCE Video Card (Purchased For $0.00)
Case: Enermax ECA3212-BL ATX Mid Tower Case (Purchased For $0.00)
Power Supply: Cooler Master i500 500W 80+ Bronze Certified ATX Power Supply (Purchased For $0.00)
Total: $166.18
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-05-15 07:50 EDT-0400
you can keep the 750 Ti and later get a better GPU..