Crysis has four basic preset quality settings: low, medium, high, and very high. The first three settings are available in Windows XP, but you'll need Windows Vista to access the very high quality setting. If you're willing to fiddle with a few files, it's not too difficult to get those settings working in Windows XP. But you probably wouldn't want to play the game with very high quality settings, as it's far too demanding for today's video cards, so it's not a huge lockout.
When it comes to individual settings, pay close attention to the shader, object, and shadow quality settings. The shader quality setting does wonders for Crysis' graphics, but every notch up slashes frame rate performance. You'll want to keep shaders as high as possible to have the game looking its best, but be prepared to lower it to keep frame rates playable. The object quality setting determines the quality and quantity of everything in the game--plant matter, bullet decals, corpses, and rocks. You can dial this setting back to reclaim some performance without a noticeable decrease in image quality, but don't reduce settings too far unless you want to transform the jungles into barren plains. Shadows take their usual toll on performance. Go ahead and set shadows to medium to achieve an acceptable balance between shadows and frame rates. Crysis doesn't really have "low quality shadows," as setting them to low simply disables them.
The Nvidia 169.04 drivers have a minor graphical downgrade that slightly increases performance in the 32-bit version of the game. We renamed the Crysis executables to disable the downgrade in our video card comparisons, but we did not rerun the settings tests with the file edits due to time constraints and the fact that we're not comparing different cards in these settings tests.
(Longer bars indicate better performance)
Resolution Tests - High Quality
Preset Quality, 1600x1200
Shader Quality, 1600x1200
Object Quality, 1600x1200
Shadow Quality, 1600x1200
System Setup: Intel Core 2 X6800, Intel 975XBX2 2GB Corsair XMS Memory (1GBx2), 160GB Seagate 7200.7 SATA Hard Disk Drive, Windows Vista. Graphics Card: GeForce 8800 GTX, Nvidia ForceWare 169.04.