Intel G45 integrated GPU supports up to 4 Monitors
 

The number of monitors supported by one system is typically limited by the number of graphics card outputs, which is a nice for Nvidia and ATI, as it enables both companies to sell their low-end GPUs as more expensive Quadro NVS and FirePro models with four display interfaces. The other alternative, of course, is DisplayLink, a company that specializes in transmitting visual data through a USB link. So far, DisplayLink support was only provided to displays that included the firm’s DP-120/160 chips.

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