This paper presents analysis of the influence of the virtualization mechanism of IBM pSeries servers on dynamic resource allocation in AIX 5L operating system. It raises issues of economic use of resources and distribution of processing power. Some innovative solutions are proposed as methods for dynamic resource allocation. These are: micro-partitioning and partition load manager utility. Some results of experiments are presented. The goal of these experiments was to estimate the influence of selected AIX 5L operating system adjustments on computation efficiency.