Microsoft released KB4482887 for Windows 10 version 1809 (October 2018 Update) on March 1st, and the headlining feature was the inclusion of Retpoline performance improvements for Spectre variant 2 mitigations. But almost immediately, gamers began reporting problems.
In one reddit thread, numerous users complained about performance problems in their games after installing KB4482887. A redditor by the name of rayw_reddit wrote:
This patch is causing massive lag spikes in older games, like CoD4 and CoD MW2. Right after installing this update, I launch any of the two aforementioned games, moving the mouse around (yes, mouse movement) causes the game to freeze in 1 second intervals every time. If you don't move the mouse, game appears fine.
The above gamer is running a pretty stout system with a Ryzen Threadripper 2950X and a GeForce RTX 2080 Ti.
"I’ve got this same issue with an RTX2080 and Ryzen 2700X," added maverick26290, "Destiny 2 has some insane lag spikes when you move the mouse. Also uninstalled this update and all is normal again." Yet another user, jenders37, wrote, "Having issues with this on several of my games as well. Destiny 2 was a NIGHTMARE, but as you said it resolved when removing the patch."
Hopping on over to the Destiny subreddit, it's more of the same, with jlobue10 writing:
I logged in to play some yesterday prior to Season of the Drifter starting this Tuesday and noticed my game was unusually sluggish. It also felt as though my mouse setting and sensitivity were messed up even though I had been comfortable with the settings I have for quite a long time now.
Now, Microsoft has officially chimed in an acknowledged that there is indeed a performance issue with KB4482887. The company confirms:
After installing KB4482887, users may notice graphics and mouse performance degradation with desktop gaming when playing certain games (eg: Destiny 2).
At this point, Microsoft says that it is working on a fix that would restore performance for affected gamers. In the meantime, Microsoft is suggesting that gamers who are experiencing issue uninstall KB4482887 for now, after which any performance lagging should be eliminated. Microsoft has not said what is causing the problems, but many are speculating that it could be in relation to the Retpoline tweaks that were implemented with this latest cumulative update.