Now that Call of Duty: Modern Warfare is here, Infinity Ward have pushed out the usual and common day-one patch with the new one for COD:MW including some PC-specific changes.
The new day-one patch includes a bunch of stuff, but starting with the PC-specific additions to Call of Duty: Modern Warfare's first patch include HDR support and the ability to use NVIDIA Highlight in multiplayer matches.
Another issue solved is an annoying FOV issue that saw the FOV reverted back to its original setting before you loaded into a round, and the ADS transition animations looking a bit funky when the frame rates were too high.
Other than that, Infinity Ward has made some small adjustments to multiplayer, including some fixes to Ground War. The new mode has been receiving a bunch of changes, with players now able to spawn on squad mates that are already in vehicles. The developer has tightened up safety checking when spawning on said teammates -- and while it can be dangerous depending on the action happening at the time you want to spawn on a teammate, the UI will now warn you before you make the move.