A patch has been released to address some performance issues on certain PC hardware configurations. Please see below for more details about this update.

PLEASE NOTE: This update contains a known issue that may cause the game to become unstable after playing for long period of time; we are currently investigating this issue. In the event that this issue is occurring frequently for you and hindering your play experience, we have made the previous version of the game ("patch 3") available for you to switch back to until this issue is resolved. Instructions for switching back to the previous version of the game are provided at the bottom of this message.

CHANGES INCLUDED IN PATCH 4

1. Improvements to help reduce frame-rate "hitching" or "stuttering" that may occur when playing the game on some hardware configurations.
• NOTE: Frame-rate consistency is best when playing with the Graphics Option titled "Lock Framerate" set to ON (i.e. v-sync enabled).
2. Fix some users being unable to switch the Texture Detail option to any setting other than Low or Very Low.
• NOTE: Users should now have all options available to them. However, playing on extremely high resolutions and/or detail levels can result in texture artifacts if the video card does not have enough video RAM to fully satisfy the memory requirements of that configuration. If this occurs, reducing resolution, graphics quality, and/or texture detail may help alleviate these artifacts.
3. Adjustments to the Mouse Sensitivity option to facilitate lowering sensitivity further
• NOTE: This may cause changes to mouse sensitivity for existing players, requiring them to re-adjust sensitivity.
4. Fix for the Nav-Aid occasionally suggesting that the player use a Sky-Line that is not currently available for use.
5. Fix for a rare crash when using a Sky-Line Strike attack on a Handyman.
6. Fix for an issue that may cause checkpoint progress to become inaccessible and appear to be lost. 
7. Changes to improve overall game stability.

HOW TO SWITCH BACK TO PATCH 3:

In the event that this update is unstable for you and you wish to switch back to the previous version of the game ("patch 3"), here is how to do so:

1. Exit and then re-start your Steam client.
2. Right click on BioShock Infinite in your Steam library and select "Properties"
3. In the Properties dialog that opens, click on the "Betas" tab
4. In the drop-down menu, select "version_patch_3"
5. Click the "Close" button