I recently purchased a Lenovo X220 with an i7-2640m, Intel Graphics 3000, Centrino Advanced N-6205, running Windows 7 64 bit. My wireless receiver is the Netgear PTV2000. Based on my research this setup meets the minimum requirements to support the wireless display function. I have updated all the required drivers to the most current versions as of yesterday. The i7-2640M is not listed on the Intel WiDi page. However the i7-2640M specifications page shows "Intel Wireless Display - Yes".
When I run the Intel WiDi setup program a window opens that shows the Netgear receiver for a fraction of a second. Then that window is replaced with an error message that says my system does not meet the minimum hardware requirement to run WiDi. There is a help link that shows a short list of required hardware which is no help. There is no message that specifically tells me what hardware is deficient.