Don't Turn Up Shadow Detail
When you're playing a game, you're always in motion, and you probably won't stop to gaze at the scenery. High shadow levels can seem very immersive--if you're standing still. If you're constantly on the move, you may notice an absence of shadows, but you'll often not see the difference between medium shadows and high shadows. Maxing out shadow levels can often cause a huge decrease in performance. Turn up this setting only after you've pumped up other image-quality settings and are still running at high frame rates.
Avoid DirectX 10 and DirectX 11 With Low-Cost Graphics Cards
Don't get me wrong: DX10 and DX11 can offer substantial increases in 3D graphics image quality. And due to improved multithreading in the DirectX libraries and drivers, installing DirectX 11 can boost performance over DirectX 10 even if the game was developed prior to DirectX 11.
However, graphics board companies do buyers a disservice by advertising cheap versions of cards as being able to run the latest graphics APIs (application programming interfaces). Technically, a Radeon HD 5450 can run DirectX 11 games in DirectX 11 mode--but the results will look like a slideshow. Revert to DirectX 9 modes if you have a low-end GPU, and you'll be pleasantly surprised by higher frame rates.
Usually you can use the in-game control panel to change the mode, but sometimes you'll need a different executable or shortcut, such as with Tom Clancy's H.A.W.X. And with some games, the way to alter the mode is not always obvious. For example, in Crysis, you enable the DirectX 9 mode by reducing the global detail settings to 'high' instead of 'very high'.
Experiment With Antialiasing Settings
Even if the game offers merely the usual 2X/4X/8X multisampling antialiasing schemes, those aren't your only choices. Here's a case where using the Windows graphics card control panel may be more useful, because you can fool around with transparency antialiasing or other modes.
You can also turn on antialiasing modes that aren't available in-game, such as nVidia's CSAA (coverage sample antialiasing), which can offer good image quality with less of a performance hit than standard multisampling antialiasing. I'll talk about those modes in the nVidia control panel section.
If your game provides more than the usual settings, experiment with them. You may find that 8X CSAA on nVidia cards looks just as good as 4X multisampling antialiasing but offers better performance.
How to Use the In-Game Controls
Now that we've looked at a few rules of thumb, let's explore in-game settings and the graphics control panels.
Most modern PC games come with a wealth of graphics options.Below I've used the recent S.T.A.L.K.E.R.: Call of Pripyat as an example, because it has assorted settings that take advantage of the latest DirectX 11 graphics cards.
Of course, if you don't have DirectX 11-capable graphics hardware, you can't enable some of these features, like tessellation, a technique that creates more-detailed geometry from a base set of geometry defined within the game.
Each additional setting you dial up or turn on can adversely affect performance. You need to determine which settings will give you the most image-quality bang for the buck, and then decide which of those to enable. The key is to remember that you're always in motion in a 3D game; you're rarely standing around and enjoying the environment.
Games that give you a wide assortment of adjustments for detail levels are terrific, and allow you to experiment to your heart's content. Since the graphics control panels from AMD and nVidia don't really let you change shadow or ambient occlusion (SSAO) settings, you have to use in-game settings if you want to balance image quality and performance.
Unfortunately, not every game gives you that much control over graphics settings. Many titles based on the Unreal Technology engine (BioShock 2 and Borderlands, for example) don't allow you to set antialiasing, one of the most basic image-quality improvements.
You can edit configuration files manually, but that might result in what programmers euphemistically call "unpredictable results"--namely game crashes, weird image-quality flaws, and more.
Next: nVidia Control Panels