Nvidia Quadro 4000 vs Nvidia Quadro K4000: What is the difference?
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Nvidia Quadro 4000 test and review - YouTube
NVIDIA Quadro K4000 VCQK4000-PB 3GB 192-bit GDDR5 PCI Express 2.0 x16 Full Height Workstation Video Card - Newegg.com
Used Nvidia Quadro 4000 2GB GDDR5 PCI Express x16 Desktop Video Card - Walmart.com
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 :