First, please go to BIOS and set 1. Primary Video Controller: GFX0-GPP-IGFX-PCI (BIOS default). 2. Surround View: Enable. 3. VIOS Type: HDMI or DVI.
Download VGA Driver : Catalyst 10-9 (V8.771.0.0) and remove other VGA drivers.
In Windows, open ATI CCC countrol panel disable Crossfile selection and save setting.
After system restart, 4 monitors will be able to support properly.