In an effort to help players fine-tune their settings to improve performance, we will explain what each of the following options do in the Video Settings menu.
First, though, to improve frame rate performance, you will need to determine whether your system is fill rate limited, polygon limited, or CPU/memory limited. There is an easy test to check if you are fill rate limited. Just change the screen resolution. For example, if changing from 1024x768 to 800x600 shows significant improvement, then your system is fill rate limited. To test if your system is polygon limited, you will need to reduce the number of polygons drawn. A good test for this is to reduce the amount of terrain drawn (either using terrain LOD, terrain detail, or terrain size). If you see significant frame rate improvements, then your system is polygon limited. If neither of these things improve performance, then your system is most likely CPU/memory limited. The best cure for a CPU/memory bottleneck is to improve the machine.
There are also other things that can cause frame rate problems such as texture thrashing, driver inefficiencies, graphics card memory, etc. Things that cause overloads on graphics card memory can create frame rate issues. Keeping the memory amount down on graphics cards can be done with almost all the settings (setting them to low), but in particular, things like the bit depths, texture detail, turning on texture compression, and screen size will show the best ways to reduce graphics card memory usage. Players with cards with 128MB of on board memory or higher on their graphics card shouldn't need to worry too much overloading memory in their graphics card.
A toggle allowing the graphics card to store textures in a compressed format. During gameplay, as new textures are loaded they are sent to the graphics card and compressed.Turning this option off is recommended
for graphics cards with large amounts of on board memory to alleviate 'stuttering' and frame rate slowdowns while loading new areas and objects during gameplay. Turning texture compression on is recommended for graphics cards with smaller amounts of on board memory.
Video Bit Depth
Video Bit depth is the number of bits that can be represented per pixel. Higher bit depths give a better color range and prevent artifacts such as color banding. Modern graphics cards will usually show no performance difference between 16 and 32 bit video depth, but using a smaller video bit depth setting will use less memory on the graphics card.
Z-Buffer Depth is the number of bits dedicated to storing Z values (Z values are the positions controlling where objects appear near or far). A higher value for Z-Buffer Depth prevent problems such as 'Z fighting' (Z fighting is the situation in which objects flicker as they are drawn in the same Z space). Modern graphics cards show no little performance differences between high and low Z-Buffer Depth settings, but setting a lower Z-Buffer Depth will use less memory on the graphics card.
Terrain LOD, or Terrain Level of Detail, controls the variability of terrain rendering during gameplay. Specifically, the polygon tessellation of terrain will be less the farther away it is. This option can provide improved frame rate performance when rendering a large number of polygons.
Terrain Detail ranges from zero to four and controls the overall polygon tessellation of terrain. A low value for Terrain Detail will draw fewer polygons to represent terrain and thus may show better framerate. However, lower terrain detail will make hills and mountains appear more pointed instead of being more rounded.
Terrain Size controls the number of terrain blocks to load and draw around the character. A low setting here will render less objects in the distance (i.e. less terrain and fewer objects that were on the terrain) and produce a higher frame rate. A high setting will draw a much larger distance and will also draw the objects on those terrain pieces farther out.
Refinement Range determines when to draw a lower level of detail object over the higher detailed one. The range is from zero to one thousand. Setting Refinement Range to zero will cause objects to be draw in their lowest detail setting close up, while a setting of one thousand will only draw objects in low detail representations far away.
Gamma controls the gamma setting for the game. Higher numbers will brighten the game whereas lower numbers will darken it. No changes in gamma should effect frame rate performance.
Particle Density controls the number of particles drawn for particle effects, such as spells. Reducing this number will draw a less 'dense' effects and may improve performance when graphics cards are fill rate limited.
Texture detail controls the quality of textures drawn in game. Changing this setting to low will render blockier textures and will improve frame rate in situations in which the game is fill rate limited. This will also reduce the amount of graphics card on board memory being used.
Dynamic lighting controls the type of lighting in the world and more specifically around the character. Using a medium setting will draw a medium bright light around the character. A low setting will turn off this light. This is largely an aesthetic choice and shouldn't effect frame rate a great deal.
Screen Resolution controls the size of the game screen to be rendered. The smaller the screen size the smaller the rendering area. This will use less memory on the graphics card and reduce the fill-rate requirements of the graphics card.
View Angle controls the field of view. This is largely an aesthetic setting, but a smaller view angle will draw less objects and can improve frame rate.
Shadow Distance controls the length of shadows draw underneath characters and mobs. This is largely an aesthetic setting and shouldn't effect frame rate.
Realtime Character Shadows
Real-Time Character Shadows are toggles for drawing shadows on the ground or onto other objects when appropriate. Turning shadows off will show some improvement in frame rate because shadows will not need to be calculated or drawn.
Normal Mapping is a advanced rendering technique for drawing small details on objects. Using an extra texture, normal mapping emulates the look of a higher detailed model by encoding light information in this texture. In the game objects that are normal mapped will appear more detailed, but will incur the need for extra texturing. This is largely an aesthetic toggle, but turning off normal mapping may improve performance in cases where on board graphics memory is low or performance is fill rate limited (this should rarely be the case because cards that can do normal mapping usually have higher amounts of graphics card memory).