Performance comparison between ThinkPad W701 with NVidia Quadro 2800M, ThinkPad X230 with Intel HD4000 and ThinkPad T520 with NVidia NVS 4200M – Ioannis Karagiorgos blog
NVIDIA NVS 4200M vs NVIDIA Quadro M5500 vs NVIDIA Quadro M4000M
Quadro - Wikipedia
A Laptop with an NVS 4200m GPU, Intel i7-2720qm CPU, is there an external GPU I could connect to it? What would you recommend? - Quora