Which build is better for gaming?

Solution
Defiantly the second build as the graphics card is much more superior over the gt 740, the processor is a decent processor for gaming as well, like you don't need 6 cores for gaming but why the hell not when its cheap :)
The amd fx 6300 will perform at a lower level than the i3 chip. But, the amd build makes up for it in the graphics department. The Nvidea Gtx 960 is far superior to the 740. The 740 is clasified as a multimedia chip as it lacks the x in gtx. Go with the amd fx 6300. I'm not sure why you are comparing these two builds though as one is worth 100 more than the other. However, you may actually be able to find a prebuilt computer with say, an i5 and a decent enough psu for you to add a better graphics unit. A good option for you to do this would be something like a 750ti.
 
Defiantly the second build as the graphics card is much more superior over the gt 740, the processor is a decent processor for gaming as well, like you don't need 6 cores for gaming but why the hell not when its cheap :)
 
Solution
How about use the i3 + gtx960 for the $630.

PCPartPicker part list: http://pcpartpicker.com/p/XyCbZL
Price breakdown by merchant: http://pcpartpicker.com/p/XyCbZL/by_merchant/
CPU: Intel Core i3-4150 3.5GHz Dual-Core Processor ($104.75 @ OutletPC)
Motherboard: Asus H81M-D PLUS Micro ATX LGA1150 Motherboard ($44.49 @ Newegg)
Memory: G.Skill Sniper 8GB (2 x 4GB) DDR3-1600 Memory ($59.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($47.89 @ OutletPC)
Video Card: Gigabyte GeForce GTX 960 2GB Video Card ($190.11 @ SuperBiiz)
Case: Enermax ECA3253-BL ATX Mid Tower Case ($37.99 @ Directron)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($37.99 @ NCIX US)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($14.98 @ OutletPC)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($88.98 @ OutletPC)
Total: $627.17
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-02-26 16:59 EST-0500