A computer system having at least one hardware unit, a control device and a plurality of virtual computer units, and a method for allocating total available computational power within such a computer system, wherein a plurality of virtual computer units can be respectively associated with a group. The computational power is allocated in a plurality of stages by using prescribed rules and taking into account allocation parameters so as to, first, split the available computational power and to allocate the split computational power to the groups and those virtual computer units which do not belong to a group, and then to split the computational power allocated to a group and to allocate the split computational power to each of the plurality of virtual computer units which belong to this group.