I built my PC for around $800-900. And i got some really decent specs.
On Max/High Settings with a full 1080p resolution monitor:
Minecraft: 200+ FPS
Battlefield 3: 60+ FPS
F1 2013: 70+ FPS
Chivalry- Medieval Warfare: 60-80+ FPS
GTA IV: 90+ FPS
Rendering DxTory files:
1omins(15GB+) takes 40-60mins(includes compression).
If you want similar performance; some of my specs are below:
Video Card:
AMD Radeon™ HD 7770 GHz Edition
Case:
NZXT SWITCH 810 ATX HYBRID Full Tower Gaming Computer Case
Motherboard:
GIGABYTE GA-970A-UD3 Socket AM3+/ AMD 970/ DDR3/ SATA3&USB3.0/ A&GbE/ ATX Motherboard
Memory:
CORSAIR Vengeance 8GB DDR3
Hard-drive:
Seagate Barracuda 1TB
CPU:
AMD FX 4100 4-Core Processor, 3.6 4 Socket AM3+
Hope it helps with your decision