Note that there is very similar issue with HD3000 Windows 7 driver version 9.x HD 3000 driver forced subpixel antialising after update to 9.x version confirmed by multiple customers having Lenovo notebook with HD3000 graphics (X220, T420, W520). It might be a clue that Lenovo machines are affected (only ?).
The issue can not be deteced by a PrintScreen and posting a screenshot, it is somewhere on driver/hardware level. A macro picture of physical notebook display must by taken by a camera to see it. It affects internal notebook display only, external DisplayPort output is not affected by the blurriness.
The only known workaround is to revert back to older 8.x driver. BIOS update does not help.