Technologies for reliable software execution include a computing device having a memory that includes multiple ranks. The computing device trains the ranks of the memory and determines a consolidated memory score for each rank. Each consolidated memory score is indicative of a margin of the corresponding rank. The computing device identifies a higher-margin address range using the consolidated memory scores. The higher-margin memory address range is mapped to a higher-margin memory rank. The computing device loads high-priority software into the higher-margin memory address range. The high-priority software may include an operating system or a critical application. A pre-boot firmware environment may publish the consolidated memory scores to a higher-level software component, such as the operating system. The pre-boot firmware environment may map a predetermined address range to the higher-margin memory rank. A critical application may request to be loaded into a higher-margin address range. Other embodiments are described and claimed.