Best Buy: XFX Double Dissipation Edition AMD Radeon R9 280X 3GB DDR5 PCI Express 3.0 Graphics Card Black R9280XTDFD
Used - Very Good: SAPPHIRE DUAL-X Radeon R9 280 Video Card 100373L - Newegg.com
AMD Radeon R9 280X 3GB HDMI PCI Express Video Graphics Card for Apple Mac Pro, outperforms ATI Sapphire Radeon HD 2600, 4870, 5770, 7950, 9000, 9800 Gigabyte : Electronics