Amazon.com: NVIDIA Quadro 400 512 MB Professional Video Graphics Card, Replacement For Lenovo 0A36535, PNY VC7400-PB, HP LD542AA LD542AT, Dell HWGX0, DDR3 PCI Express Gen 2 x16 DVI-I DL and DisplayPort Open
IBM - NVIDIA Quadro Quadro 400 (512MB GDDR3) Graphics
NVIDIA GeForce GTX 400 Series - What you need to know
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Update: NVIDIA's GeForce GTX 400 Series Shows Up Early