In November 2025, some NVIDIA users noticed reduced game performance after installing Windows 11 update KB5066835. My original post discussed CS2 frame-rate drops and the 581.94 hotfix released around that time.

NVIDIA’s original support link and its 581.94 release notice identify lower performance in some games after the October 2025 Windows 11 update. This did not establish a universal percentage loss or a guaranteed frame-rate improvement on every PC.
At the time, the steps were to download the official hotfix, install it normally, and restart. For a problem you are diagnosing now, first check your exact GPU, Windows build, and installed driver, then use NVIDIA’s currently supported release and notes. Installing an old hotfix solely because its number appears in a historical guide may be unnecessary.

If performance changed right after an update, comparing the same game settings and scene before and after a supported driver update is more useful than an isolated peak FPS reading. I did not notice a dramatic extra boost after the fix, even though it addressed the problem described in NVIDIA’s notice.
Adapted from the original Chinese article, published on November 28, 2025.

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