Assassin’s Creed Shadows Affected by Performance Issues From Windows 11’s KB5066835 Patch

Digital Foundry confirmed this with performance figures for Assassin's Creed Shadows, and criticised Microsoft's stewardship of the OS.

Posted By | On 26th, Nov. 2025

assassin's creed shadows

Digital Foundry has confirmed with testing that a recent Windows update – released in October and known as patch KB5066835 – has resulted in a major performance downgrade for games. In a recent episode of its weekly podcasts, the hosts discussed the recent update, and went as far as to call it “not fit for purpose at this point in time”.

While the hosts largely discuss the recent issues with the operating system, Alex Battaglia goes into quite a bit of detail about how gaming performance has been impacted for Windows 11 users. He also noted that the silent nature of the update happening automatically in the background added even more to users’ frustration.

Along with this, Battaglia also spoke about how the performance issues had largely gone unnoticed by many until Nvidia released a driver hotfix for its graphics cards that acknowledged the lower performance on Windows 11 and aimed to fix it. Interestingly the performance issues are most visible in a few games, including Ubisoft’s Assassin’s Creed Shadows.

“That KB patch silently destroyed performance in at least two games,” said Battaglia. “The one I tested for this segment is Assassin’s Creed [Shadows]. I loaded it up and I was like ‘oh this runs like ****.’ And I knew that something was wrong. So I double checked, and after having installed the hotfix driver you can see how big of an issue this is.” He follows this up by showing side-by-side video comparisons of the title’s performance before and after the hotfix driver’s installation.

Before Nvidia’s hotfix was applied, running Assassin’s Creed Shadows on the Windows 11 update in question with overpowered hardware – an AMD Ryzen 7 9800X3D CPU and an Nvidia GeForce RTX 5090 GPU – and visuals set to 4K and the max preset and DLSS set to Quality resulted in an average frame rate of around 34 FPS. After the hotfix driver, the frame rate went all the way up to 71 FPS, which is noted as being a performance boost of around 206 percent.

When it comes to just how this Windows 11 patch was released, Battaglia noted that there might be a few reasons, such as there being some sort of issue with how Nvidia’s graphics cards tap into the DirectX APIs. However, he said that Microsoft shouldn’t be releasing a stealthy operating system update that breaks things. Rather, the company should be telling Nvidia that there is a problem.

“If it wasn’t an Nvidia [DirectX] conformity issue, this means Microsoft is releasing patches to Windows that [the company] is not sure what [the patch] is doing,“ said Battaglia. “It is silently killing performance in games, and you are left with the user, or Nvidia after the fact, or AMD or Intel, having to figure this out via their own testing regimens. Hence why, more than a month later, we see an update here from Nvidia.”

“The timing is just really bizarre, and I don’t think it paints a really good picture here of how Microsoft stewards the operating system, regardless of who, at the end of the day, is responsible for the actual issue occurring. Because they’re the one updating their operating system, and maybe you should delay that patch until Nvidia actually has proper support for it in a driver to fix the conformity issue.”

Battaglia also spoke about future plans considering the current downward trajectory of Windows 11, and how maybe he will start investigating a move to Linux for his PC gaming needs instead.


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