Bioshock performance and graphics can be enhanced by tweaking the configuration files. You can refer to the Tweak Guide below to optimize Bioshock for performance and enhance its graphics.
First off, you need to open the configuration files of Bioshock with a notepad; these can be found in following locations.
\Documents and Settings\[Username]\Application Data\Bioshock directory (in Windows XP)
\Users\[Username]\AppData\Roaming\Bioshock (in Windows Vista).
These files are hidden so you’ll have to change that first.
Bioshock Tweak Guide
Open configuration file with a notepad and do the following tweaks for the specified changes.
It determines which API the game uses for graphics and the only choices are DX9 (D3DDrv.D3DRenderDevice) or DX10 (D3DDrv10.D3DRenderDevice10).
It determines which Audio API is used.
The value determines the amount of system Ram set for caching game information. Increasing it will reduce loading pauses in game.
The value controls the resolution of the game running in windowed mode.
These values control the resolution of the game in fullscreen mode.
You can adjust the Contrast and overall Gamma of the picture using these settings.
This setting controls the way mouse movement is recorded by the game.
These settings control how magnified your mouse movements are.
As noted above, BioShock uses the FMOD audio engine, and not the generic OpenAL (ALAudio.ALAudioSubsystem) engine. Therefore only the settings under this section and audio-related options under the ShockGame.ShockUserSetting section further below affect the audio in the game.
This option controls the maximum number of individual audio channels used for sound in BioShock.
This option determines the buffer size in KB for each audio stream. Lower it to prevent audio stuttering.
It is worth noting that the above settings in combination are the same as the in-game Actor Detail setting. When both are False this is the same as Low Actor Detail; when both are True this is the same as High; and when only the first is True this is equal to Medium.
If set to True allows the game to precache a range of graphics data. This helps reduce loading pauses, choppiness and hitches in the game.
If set to False this option disables Trilinear Filtering and uses basic Bilinear Filtering for textures instead.
Reduces mouse lag and fps at the same time.
Reduces mouse lag when Vsync is enabled.
If you have VSync enabled then your Refresh Rate will be limited to whatever this setting is.
This setting controls the level of Anisotropic Filtering used in BioShock.
This setting allows you to exceed any refresh rate limitations Windows imposes.
Hitches are small pauses/stutters, caused by your system pausing to load new data. If set to True, this setting may help reduce the occurrence of substantial hitches in the game, but it can also reduce average framerates, so leave this option at False unless you have very serious stuttering issues.
Saves graphics memory when on true but results in a very noticeable reduction in image quality.
This render device is only used when running Windows Vista with a DX10-capable graphics card.
When DX10 mode is being used, this option is set to True by default. Shadows in the game will be even sharper and more detailed.
Leave it be as it is.
This setting controls the maximum number of separate ‘threads’ on which the Havok physics engine may run.
It seems to have no impact at all on image quality or performance whether enabled or disabled.
When DX10 mode is being used, this option controls the additional ripple physics effects used on water.
When DX10 is enabled this enables soft particles.
This setting appears to determine whether cube mapping is used on certain specular (shiny) surfaces. Setting it to false can cause some graphical glitches (e.g. on melting ice), so it is not recommended.
Should be set to True for optimal performance if you have a multi-core system.
Sets the in game mouse sensitivity.
By default the game makes sure that you automatically hit enemy targets with things like electro-bolts as long as the target is anywhere within your red circular aiming reticule. Setting this option to False removes this auto-aim tendency for Plasmids.