buying a new gaming pc need help please !!

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hi guys i want to buy a new pc for gaming this week soo i really dont know much about brands but i really want to know wich part and why this is better sooo if u can explaint if gonna be great.
i want this pc for essentially run games in 1650*1200 in full graphics ( WOW, D3 , TERA , GW2, AND BATTLEFIELD) especially BATTLEFIELD.
P:S crossfire can be a good choise ,overclock , and thinks like this???
i can spend around 1.k to 1.2k o maybe a little more
thanks for all guys

[Deleted]

Something like this may suit you then.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-2500K 3.3GHz Quad-Core Processor ($169.99 @ Microcenter)
CPU Cooler: Xigmatek GAIA SD1283 56.3 CFM CPU Cooler ($29.99 @ Newegg)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($139.99 @ Microcenter)
Memory: G.Skill Sniper Low Voltage Series 8GB (2 x 4GB) DDR3-1600 Memory ($51.99 @ Newegg)
Hard Drive: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($67.99 @ SuperBiiz)
Hard Drive: Crucial M4 128GB 2.5" Solid State Disk ($114.99 @ NCIX US)
Video Card: Gigabyte GeForce GTX 670 2GB Video Card ($399.99 @ Newegg)
Case: Corsair 400R ATX Mid Tower Case ($89.99 @ Newegg)
Power Supply: SeaSonic 620W ATX12V / EPS12V Power Supply ($87.99 @ SuperBiiz)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($98.99 @ B&H)
Total: $1251.90
(Prices include shipping and discounts when available.)

Could get a 3570K instead, it's a bit more expensive but the difference actually isn't that big when you overclock them. This computer will play all games on max @ 1680x1050(assuming that is your resolution, never heard of the one you mentioned). If you want to save money, drop down the GPU to the Radeon 7870 ($300).