AEST tries to find, parse, and translate as much Alpha code as possible to minimize the need for interpreting Alpha code at run time. By default, AEST uses the EISD$V_EXE ISD flag to translate all code that it finds in image sections marked as "executable". If you specify /INTERPRET, AEST still analyzes all the code found in "executable" Alpha image sections and creates corresponding structures in the resulting I64 image, but it did not generate corresponding I64 code. This minimizes the AEST execution time and virtual memory required for translation. Note that run-time performance of a translated image using /INTERPRET will be slower than one where the code is translated.