In a system with hardware main memory compression, the method of this invention monitors the physical memory utilization and if physical memory is near exhaustion it forces memory to be paged out, thus freeing up real memory pages. These pages are then zeroed, thus they are highly compressible and therefore reduce the physical memory utilization. Pages that have been forced out due to high physical memory utilization are not made available for allocation. In systems where operating system changes are permitted, this invention dynamically controls the minimum size of the free page pool and zeros pages upon freeing. When the physical memory utilization falls below a critical threshold the mechanism reduces the minimum size of the free pool to allow further allocation. In systems where operating system changes are not possible, pages are allocated by a module (e.g. Device driver) and then zeroed. When the physical memory utilization falls below a critical threshold this method frees some of the explicitly set aside pages.