Amazon.com: NVIDIA Quadro 4000 2GB GDDR5 256-bit PCI Express 2.0 x16 Full Height Video Card (Renewed) : Electronics
Amazon.com: Nvidia Quadro 4000 2GB GDDR5 256-bit PCI Express 2.0 x16 Full Height Video Card with Rear Bracket (Renewed) : Electronics
nVidia Quadro 4000 2GB Graphics Video Card for Mac Pro Dual DVI CUDA : Amazon.co.uk: Computers & Accessories
Amazon.com: NVIDIA Quadro 4000 for Mac by PNY 2GB GDDR5 PCI Express Gen 2 x16 DVI-I DL, DisplayPort and Stereo OpenGL, DirectX (Boot Camp), CUDA and OpenCL Profesional Graphics Board, VCQ4000MAC-PB :
NVIDIA Launches Quadro 4000 GPU for Mac Pro - MacRumors
NVIDIA Quadro 4000 2GB GDDR5 Video Card VCQ4000-PB