Switching between Video Adapters in a Dell Latitude E6530 laptop

Question

I have a Win 7 Latitude E6530, which includes a discrete graphics card (nVidia MVS 5200M), normally connected via the Port Replicator to 2 external monitors (Dell U2410 + Dell 2001FP) both via DVI.

In the past I could use the 3 monitors (2 externals and the built in) in an extended desktop configuration. I vaguely remember that the control panel display applet indicated that the active display adapter was the Intel Graphics one.

A couple of months ago, after removing the laptop from the dock for the first time after a long period, something happened, and I can no longer use 3 monitors. The control panel says I now use the MVS 5200M card as the active adapter, and it is limited to 2 monitors (choose 2 out of the 3).

I could not find where I can restore the old setup. Is there some configuration dialog that I missed?

Solution

Following this question, it turns out that I had to enable the Optimus feature in the BIOS. Once this was done, I had to play a little with the settings, but eventually, I have a 3 monitors setup working now. The NVS 5200M adapter drives the two external monitors, while the Intel Graphics drives the built-in laptop monitor.