Every so often, the game you play will experience some form of slowdown on the screen, making it unplayable. Perhaps it's a sign that your current graphics card is no longer up to the job; but before you consign it to the scrapheap, there are some things you can do to try and increase the game's performance.
Lower your resolution
Lowering the resolution you run the game at can save you several frames per second and turn an unplayable game into a playable one. If you don't want to sacrifice detail, but are experiencing a lot of stuttering, jerky gameplay, try dropping the resolution down a notch.
If you are using an LCD monitor, try running the game at a level lower than the native resolution of your monitor.
Lower the Shadow Detail setting
Shadow detail can have a huge bearing on the frame rates of your game. It may be worth dropping the level of shadow detail down a level or two.
If you have V-sync enabled, try turning it off. V-sync prevents the next frame being displayed until it has been fully rendered in the frame buffer and is often undesirable, especially in games that require fast responses, such as first-person shooter games.
Anti-aliasing & Anisotropic Filtering
Having one or both enabled can adversely impact on game and system performance. Try lowering the detail of one or both; or turning them off altogether.
Level Of Detail
Many modern games will have a setting whereby you can determine the level of detail, which will define such aspects as water ripples, dynamic lighting, texture mapping and others. Try turning the setting down one level.
Some games will offer separate detail options for effects such as water ripples and reflections. These may need to be adjusted separately.
Toning down dynamic lighting can also have a big effect on a game's frame rates.
Look for settings such as number of bodies displayed, blood effects, etc... having these set too high can cause the game to slowdown. Keeping the numbers down can help improve framerates.
Visit the game publisher's website to see if the problem you are having is a known issue. There could be a patch or hotfix available for the affected game which could solve the problem.
Visit your graphics card vendor's website and download the latest driver for your graphics card. It may also be worthwhile to make sure you have the latest version of Direct X installed on your system.
Before you begin playing a game, you should close down any non-essential programs that are running in your system tray. You don't really need your email program running while you're playing games, for instance.
In the majority of cases, tweaking the in-game settings to a level that's less strenuous on your system's hardware can result in noticeable gains in system performance and allow you to play games at an altogether more acceptable level.