The output value at startup of the Stratix and Cyclone series internal memory blocks depends on which block type you are using and whether you are using a register for the output port.

The types of memory blocks owned by each device are:
・Stratix IV / Stratix III: MLAB, M9K, M144K
・ Stratix II / Stratix: M512, M4K, M-RAM
・Cyclone III: M9K
・ Cyclone II / Cyclone: M4K

Also, the output values at startup for the memory block type are as follows.
・ M512: "0" (zero)
・ M4K: "0" (zero)
・ M-RAM: "0" (zero) when using the output register
Undefined if unused (* initial value cannot be set)
・ MLAB: "0" (zero) when using the output register
If not used, the contents of the initial value file (hex or mif) are reflected.
・ M9K : "0" (zero)
・ M144K : "0" (zero)

The type of memory block can be specified when setting parameters in the MegaWizard Plug-In Manager. If you select Auto at that time, it will be automatically selected by the Quartus II Compiler.
For Auto, check the compiler report to see which block it was placed in.