Is it possible to use three screens with Intel HD 3000 integrated graphics?
No, according to Intel's FAQ on the HD 3000 integrated graphics:
No. Intel® graphics products can output to one or two display devices at the same time. More than two display devices can be physically connected, but only two display devices can be used at any time.
However it seems you can use a splitter to "clone" a third monitor.
Some customers report being able to use third-party video splitter devices to allow output to more than two display devices. Intel has not tested these configurations nor can make recommendations on these third party devices.
Keep in mind cloning only mirrors exactly what is on one of the two monitors it will not be an independent third monitor.
As already answered you just have 2 concurrent outputs. But you can split it (it's not mirroring).
So you take a big resolution (e.g. 3200x1200) and split it into two (e.g. 2x 1600x1200). You need to have these resolutions (there are some possibilities). I done it years ago with triple split (1 output to 3 monitors) for creating a cave with one graphics card.
I'm running three displays on an HP EliteBook 8460P with Intel HD 3000 graphics adapter:
- DVI port to HDMI Hanspree HF199H at 1440×900 (recommended). 1920×1080 works but overscans the physical screen. That might be adjustable.
- USB 3.0 port to Insignia USB to VGA to Dell S2330MX at 1360×768 (max that works)
- Built in 14 inch display at 1366×768 (recommended)
I'm extending across the three displays – not mirroring.