XFX Radeon R9 280X 3GB GDDR5 PCI Express 3.0 x16 CrossFireX Support Double Dissipation Edition Video Card R9-280X-TDFD GPUs / Video Graphics Cards - Newegg.com
Amazon.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