Though adding memory helps, the following tips will greatly improve your PC performance without any additional cost.
1.) HARDWARE - Make sure your PC has the recommended specs at the very least for all your games.
2.) DO NOT USE FANCY GAME VISUALS - maxing out antisotropic, antialiasing, shadows, and resolution. Settings like trilinear, 800×600 resolution, lower shadow settings, etc. can dramatically improve performance with very little visual difference. Good framerates should be your first priority, not fancy graphics. Let your framerates dictate your graphic settings by making sure you’re running at least 30 frames/second.
3.) DEFRAGMENT - Defragment your HD frequently, preferably once every week. A clean HD is a healthy HD.
4.) SCANDISK - Much like the defragmentation tool, scandisk is another good practice, but I would say only needs to be done monthly.
5.) VIRUS/SPYWARE SCANS - Always scan for viruses/spyware, at least once every week. Norton Antivirus and Spybot are popular.
6.) DO NOT USE VISTA - Vista doesn’t have enough support and multiple benchmark tests have proven it reduces performance.
7.) CLEAN THE CASE - Dust always finds a way to sneak its way in and can heat up your components, clean weekly.
8.) GOOD AIR/WATER circulation - Good fans and or watercooling can dramatically lower hardware temperatures and lower temperatures lead to…..
9.) OVERCLOCKING - Overclocking leads to better performance.
10.) REFORMAT - Reformat your HD once every year, although every half a year is an even better practice . This helps clean out your HD from stuff virus/spyware scans can’t catch.