- Windows 11 October update may have introduced a nasty gaming bug
- This affects Nvidia GPUs and Team Green released a fix last week.
- However, we did not know how serious the bug was, and tests show that the frame rate can be huge: in Assassin’s Creed Shadows, it slows down performance by 33% to 50%.
Nvidia released an emergency patch last week for an issue that may have been caused by the windows 11 October Update, and now we have evidence showing how this bug has caused severe frame rate issues in some games.
Definitely a specific game. Digital casting I did some tests with Assassin’s Creed Shadowswhich was pointed out by many Windows 11 players who complained that Microsoft’s October patch (KB5066835) significantly slowed down frame rates.
And those reports weren’t exaggerated given Digital Foundry’s benchmark, which showed frame rates to be high Assassin’s Creed Shadows They slowed down by at least 33% and at worst up to 50% or more.
This was done on a gaming PC equipped with a Ryzen 7 9800X3D CPU and an Nvidia RTX 5090 graphics card. There are screenshots showing that this powerful GPU has been reduced to 34fps (4K DLSS quality) with the patch and running at 72fps without the October updates.
Nvidia forgot to say which games were affected and needed the emergency patch to save them, but it’s pretty clear Shadow was one of them. Digital Casting Clocks Counterattack 2 It seems to be another title that suffers from choppy frame rates.
Analysis: A mysteriously vague and rather unpleasant bug
It’s definitely a weird issue, and it doesn’t help that Nvidia has been vague when talking about this bug, only saying it affects game performance on certain titles, without mentioning which games or even what kind of performance issues it causes.
It’s really eye-opening how tests like this show that the performance is huge, at least in this case. Assassin’s Creed Shadows – This is a defect that can literally bring the RTX 5090 to its knees, as we can clearly see. Good luck with a weaker Nvidia GPU.
There is at least one workaround, but you have to find and install it manually (i NVIDIA website) – and remember that this is a beta version. However, the fully tested and finished solution comes with the next version of the Nvidia driver.
If you don’t want a beta version, and you’d understand why, since it’s also software guaranteed to cause no more problems, a suggested complicated solution is to disable the customizable bar feature (in the BIOS). This doesn’t completely alleviate the delay caused by the October update, but it fixes the messages. redditMinimizes frame rate drops.
The real question is: what is causing this problem? Nvidia is indirectly implying that Microsoft is to blame by saying that the problem occurs “after Windows 11 October 2025 update KB5066835”, although this is not an explicit assignment of blame. This does not rule out a problem in the Team Green drivers that was somehow discovered by the changes Microsoft made in the update (after all, AMD or Intel GPUs are not affected).
We just don’t know the reason and it’s generally not an ideal situation. Microsoft or Nvidia, or both companies, may need to investigate further. Anyway, I’ve contacted Microsoft to see if the company can explain why this happened and I’ll update this article if I hear back.