i ve an old dell system dell optiplex 960, i ve 8bg ddr 2 ram, which definitely does nt enough for performance, currently i m using win 7 home premium, 3.0 Intel processor names as e-8400, plz tell me that what is a virtual memory and can we increase pc's overall performance ( including games ) ? if yes then how it works and what is the limit or perfect value to increase it.