The PSU only puts out 3 voltage levels, viz. 3.3V, 5V, and 12V. There is also a separate 5V output for standby purposes. VBAT is the voltage of the CR2032 battery that maintains the data in the CMOS. All these voltages are within the acceptable tolerance range for ATX PSUs. The CPU Core and 2.5V (which I assume is the memory) voltages are derived from the main 12V supply via the on-board voltage regulators, and the actual level of these at any given time can vary according to load and demand.