A nonvolatile memory apparatus includes a memory device including a configuration information storage block for storing configuration data groups. A configuration information processing circuit is configured to determine majorities of configuration data groups, which are outputted from the memory device during a first period as an initial stage of a power-up operation, under the control of a first control clock signal. The configuration information processing circuit is also configured to determine majorities of configuration data groups, which are outputted from the memory device during a second period after the first period, under the control of a second control clock signal having a cycle shorter than the first control clock signal.