Kelthar :
Exactly. The CPU will never bottleneck the GPU, that's why the money spent on getting getting slightly higher clock rates should be put into getting a better GPU, which is the current bottleneck.
There is still nothing in his price range under $400 that will give him significant performance boost... I still believe in aftermarket cooling, even for the sake of temperature. I edited my rig and found an r7 260 which should be better.
PCPartPicker part list:
http://pcpartpicker.com/p/36yRP
Price breakdown by merchant: http://pcpartpicker.com/p/36yRP/by_merchant/
Benchmarks: http://pcpartpicker.com/p/36yRP/benchmarks/
CPU: AMD Athlon X4 750K 3.4GHz Quad-Core Processor ($79.98 @ OutletPC)
CPU Cooler: Thermaltake CLP0605 79.3 CFM CPU Cooler ($19.99 @ Newegg)
Motherboard: Gigabyte GA-F2A88XM-D3H Micro ATX FM2+ Motherboard ($64.99 @ NCIX US)
Memory: Kingston Beast 8GB (2 x 4GB) DDR3-1600 Memory ($83.54 @ Amazon)
Video Card: MSI Radeon R7 260 1GB Video Card ($89.99 @ Newegg)
Power Supply: Corsair Builder 500W 80+ Bronze Certified ATX Power Supply ($29.99 @ Newegg)
Optical Drive: LG GH24NS95 DVD/CD Writer ($20.49 @ Amazon)
Total: $379.97
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-08 21:10 EST-0500)