Why do Stratix V C1 and I1 speed grade devices show incorrect voltage in the Device settings dialog box?

Due to a reporting issue in the Quartus® II software version 11.1SP2, the Device settings dialog box shows incorrect core voltage for Stratix® V C1 and I1 speed grade devices. The Device settings dialog box shows 0.85 V but the correct voltage is actually 0.9 V.

For the actual voltage setting, open the Quartus II Settings dialog box by selecting Settings from the Assignments menu. In the category listing, expand the Operating Settings and Conditions category and select Voltage. The VCC Voltage for Stratix V C1 and I1 speed grade devices is correctly shown as 0.9 V.