Where is the saved BIOS configuration data stored?

All the settings from the BiOS are stored in a chip which is located on the motherboard. That chip is called EEPROM (electrically erasable PROM).
BiOS configuration setting is store in special memory called CMOS. Which is little powered by a battery. RAM is volatile so when computer turned off, all data lost.

This can also happen with CMOS but due to this purpose it is powered by battery. It consumption of power is very low and it can store data for 1 year.

CMOS stand for "Complementary Metal Oxides Semiconductor".