Re: 6870 Black edition worth it?
Yes, I've seen cards overclocked so that they are up to 300 mhz higher, and since you are going to have the coolermaster HAF 912, and a dual fan design, I'm positive you could do that.
ENERMAX LuxuRay ATX Mid Tower Computer Case
AMD Phenom II X4 955 Black Edition 3.6 GHz
XFX Radeon 6870 256-bit 2GB
ASUS M5A97 AM3+ AMD 970 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
Seagate Barracuda 500GB 7200 RPM SATA 6.0Gb/s 3.5" Internal Hard Drive
Kingston HyperX 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600
RAIDMAX HYBRID 2 RX-730SS 730W ATX12V V2.2/ EPS12V SLI Ready CrossFire Ready Modular
Sony Optiarc CD/DVD Burner Black SATA Model AD-7260S-0B - OEM
Microsoft Windows 7 Home Premium