CPU - Either an i7 or a high end i5. A top end AMD quad core might be fine, but my personal recommendation is for an Intel. RAM - DDR3 is the fastest RAM currently available. I'd go for at least 6-8GB for future-proofing. GPU - You'll need DX11 for games in the next few years, so your current choice is only ATI. Go for 5870 if your screen is under 1920x1200, 5970 if it's bigger. HDD - Forget SCSI. Seriously. Get a 160GB SSD (Intel or one with an Indilinx controller) for your C drive and get a 2TB HDD for your D drive to hold all your files. videos, etc. PSU - Go for a quality brand of at least 850W. That should keep you running sweet for years. If you're going for the 5970 or are likely to go Crossfire or SLI on future GPUs later, I'd probably stretch to 1000W. Make sure it's a quality brand.And using a free duplicate file finder can also be good for PC health.
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Processor Intel Core i5-2500K Sandy Bridge-based 3.3 GHz CPU Cooling system Cooler Master Hyper 212 Plus CPU Cooler Cooling system 2 x Kingwin CF-012LB 120 mm Case Fan Cooling system 2 x Cooler Master R4-L2R-20AC-GP 120 mm Motherboard Gigabyte GA-Z68XP-UD3-iSSD LGA 1155 Motherboard w/ 20 GB SSD RAM G.Skill Ripjaws 8 GB DDR3-1333 Kit (2 x 4 GB) Graphics Card 2 x Galaxy 58NLH5HS3PXZ GeForce GTX 580 1.5 GB Hard Drive OCZ Agility 3 120 GB Hard Drive Samsung SpinPoint F4 HD204UI 2 TB 7200 RPM 3.5" Hard Drive Case Rosewill Future Mid-Tower Power Supply Corsair TX950 950 W Power Supply DVD Burner LG 12x WH12LS30 Blu-ray Burner.