Nvidia’s newest GeForce Game Ready Driver, version 591.44 WHQL, folds a rushed hotfix into a full, certified release and restores gaming performance on Windows 11 systems that regressed after Microsoft’s October 2025 cumulative update (KB5066835). The driver shipment, published in early December 2025, is more than a routine compatibility update — it reconciles a cross-vendor regression that left some users seeing major frame‑rate collapses, brings back legacy 32‑bit PhysX GPU acceleration for select titles on Nvidia’s RTX 50‑series, and bundles a long list of gameplay and creative‑app bug fixes that make it a high‑priority installation for affected users and many content creators alike.
Windows 11’s October 14, 2025 cumulative update (KB5066835) shipped as part of Microsoft’s Patch Tuesday cycle and included a mix of security hardenings, platform improvements, and feature rollouts. Within days of the update, gamers and benchmarking outlets began reporting sudden drops in frame rates and stuttering in a subset of modern titles on systems running GeForce drivers from the R580 branch and newer. Reports ranged from modest degradations to dramatic falls — in isolated cases users and testers documented drops approaching or exceeding 30–50% in specific scenes.
Nvidia responded by issuing a targeted hotfix — GeForce Hotfix Display Driver 581.94 — in mid‑November 2025 as a rapid mitigation. That hotfix was deliberately small in scope and distributed outside the usual WHQL/Studio cadence to get relief to impacted users quickly. The fixes incorporated into that hotfix have now been merged into the fully certified Game Ready Driver 591.44 WHQL, published in early December 2025, which should reach users through the normal download channels and the Nvidia app.
It’s important to recognize that the widely reported “up to half your frame rate” figures represent extreme, scene‑specific observations rather than a universal average. For most users the impact was inconsistent and depended on the title, GPU generation, driver branch, CPU, anti‑cheat/overlay stacks, and even background software.
Version 591.44 restores GPU‑accelerated 32‑bit PhysX for a curated list of legacy titles on RTX 50‑series cards. The practical effect for players of those games is:
Caveat: the re‑enablement is selective — not every old PhysX game will be returned to GPU acceleration — and the list of supported titles is controlled and limited.
Important: the exact root cause internal to the Windows update and how it exposed the regression has not been publicly detailed by either vendor in exhaustive technical terms, so any precise attribution remains speculative unless an official post‑mortem is published.
For the typical enthusiast or creator who encountered the KB5066835‑related slowdown, installing 591.44 is the right move. For users who didn’t see regressions and whose workflows are sensitive to even minor changes, a short delay and routine verification is a prudent approach. In every case, the incident underscores a larger truth: the PC ecosystem’s complexity means single OS updates can interact unpredictably with device drivers, but vendor responsiveness, combined with conservative deployment strategies by users and admins, can blunt the fallout.
In short: if your system felt the hit after October’s Windows update, install GeForce Game Ready Driver 591.44 WHQL to regain performance, validate your most important workloads after installation, and keep an eye on driver notes and community reports for any follow‑up fixes or adjustments.
Source: eTeknix Nvidia Game Ready 591.44 Driver Restores Lost Performance in Windows 11
Background
Windows 11’s October 14, 2025 cumulative update (KB5066835) shipped as part of Microsoft’s Patch Tuesday cycle and included a mix of security hardenings, platform improvements, and feature rollouts. Within days of the update, gamers and benchmarking outlets began reporting sudden drops in frame rates and stuttering in a subset of modern titles on systems running GeForce drivers from the R580 branch and newer. Reports ranged from modest degradations to dramatic falls — in isolated cases users and testers documented drops approaching or exceeding 30–50% in specific scenes.Nvidia responded by issuing a targeted hotfix — GeForce Hotfix Display Driver 581.94 — in mid‑November 2025 as a rapid mitigation. That hotfix was deliberately small in scope and distributed outside the usual WHQL/Studio cadence to get relief to impacted users quickly. The fixes incorporated into that hotfix have now been merged into the fully certified Game Ready Driver 591.44 WHQL, published in early December 2025, which should reach users through the normal download channels and the Nvidia app.
What went wrong: Windows update, driver interaction, and real‑world impact
The regression and its scope
After KB5066835, multiple independent tests and many user reports signaled a performance regression on affected Windows 11 systems when running some GPU‑heavy games. The symptoms included:- Reduced average frame rates in gaming benchmarks and real gameplay.
- Increased stuttering and worse frame pacing in fast‑moving titles.
- Wide variability between systems — some rigs showed little to no degradation while others experienced dramatic slowdowns.
Laboratory and community evidence
Independent publications and community benchmarking screenshots showed sizable recoveries once Nvidia’s hotfix was applied. Examples included scene‑specific comparisons where a frame rate increased from the mid‑30s to the low‑70s FPS, and other user tests showing large gains in 1% lows. At the same time, other tests showed only modest improvements or none at all, which underlines that the regression was not uniformly reproducible across configurations.It’s important to recognize that the widely reported “up to half your frame rate” figures represent extreme, scene‑specific observations rather than a universal average. For most users the impact was inconsistent and depended on the title, GPU generation, driver branch, CPU, anti‑cheat/overlay stacks, and even background software.
The hotfix and the WHQL driver: what 591.44 brings
Timeline and certification
- Nvidia released the hotfix 581.94 on November 19, 2025 to rapidly address the performance regression affecting systems updated with KB5066835.
- Nvidia then integrated those hotfix fixes into the mainstream driver lineage and shipped GeForce Game Ready Driver 591.44 WHQL on December 4, 2025 as the stable, certified release for broader distribution.
Key fixes and additions in 591.44 WHQL
- Restores performance for systems affected by Windows 11 KB5066835 — the core mitigation folded in from the hotfix branch, aimed at the frame‑rate and stuttering regressions some users saw.
- Re‑enables 32‑bit GPU‑accelerated PhysX for select legacy titles on GeForce RTX 50‑series GPUs, reversing a prior limitation that had forced PhysX onto the CPU on those cards.
- Fixed gaming stability and performance issues in a number of titles, including:
- Battlefield 6 — improved stability and Game Ready optimizations for the Winter Offensive content.
- Black Myth: Wukong — resolved lower performance observed on drivers newer than the R570 branch.
- Counter‑Strike 2 — corrected rendering anomalies where text could appear distorted under certain resolution/scaling scenarios.
- Monster Hunter World: Iceborne — particle effect restoration on RTX 50 GPUs.
- The Witcher 3: Wild Hunt — corrected intermittent sword corruption artifacts.
- Fixed creative‑app issues, including an Adobe Premiere Pro freeze that could occur during hardware‑accelerated exports on some configurations.
- Addressed RTX 50‑series Chromium video artifacts (e.g., a green line during playback) and several other stability and compatibility fixes.
- DLSS 4 and Game Ready updates for high‑profile releases such as Battlefield 6: Winter Offensive and Call of Duty: Black Ops 7, including improvements to DLSS Ray Reconstruction quality.
The PhysX reversal: what it means for legacy games
Nvidia’s RTX 50 family initially lacked 32‑bit CUDA support, which meant many older games that relied on 32‑bit PhysX libraries fell back to CPU processing or produced degraded physics effects. That shift caused performance and visual deviations in classics such as Borderlands 2, Mirror’s Edge, Batman: Arkham City, and several others.Version 591.44 restores GPU‑accelerated 32‑bit PhysX for a curated list of legacy titles on RTX 50‑series cards. The practical effect for players of those games is:
- Restored particle, ragdoll, and cloth simulations driven by the GPU rather than the CPU.
- Improved visual fidelity where PhysX was used for atmospheric or particle effects.
- Better performance in titles that previously suffered steep CPU load increases after PhysX was forced onto the CPU.
Caveat: the re‑enablement is selective — not every old PhysX game will be returned to GPU acceleration — and the list of supported titles is controlled and limited.
Technical analysis: likely causes and why the fix matters
Understanding exactly why an OS cumulative update causes driver‑level performance regressions requires access to internal telemetry and logs from both Microsoft and Nvidia. At a high level, however, plausible explanations include:- Changes in kernel mode scheduling, interrupt handling, or power management that altered how the GPU driver’s workloads were prioritized.
- Revisions in graphics‑related subsystems or API surface in the OS that produced edge‑case misbehaviors for certain driver code paths optimized for prior Windows builds.
- Interactions with third‑party software (anti‑cheat, overlays, capture utilities) that surfaced only under the new OS behavior and exposed latent timing or synchronization issues.
- Subtle differences in platform behavior across CPU microarchitectures or BIOS settings that made the regression detectable on some systems but not others.
Important: the exact root cause internal to the Windows update and how it exposed the regression has not been publicly detailed by either vendor in exhaustive technical terms, so any precise attribution remains speculative unless an official post‑mortem is published.
What gamers and creators should do now
For affected gamers
- If you observed degraded performance after installing Windows 11 KB5066835, install GeForce Game Ready Driver 591.44 WHQL through your normal Nvidia driver channels or via the vendor’s official download tool. This will apply the hotfix corrections in a fully tested package.
- If you did not experience performance problems, installation is still advisable for the general set of bug fixes and game optimizations in 591.44, but you may elect to wait a short window to allow broader community feedback to surface any rare regressions.
- For competitive players requiring maximum stability, consider:
- Creating a system restore point or backing up key profiles.
- Installing the driver in standard mode; if you run modded or experimental overlays, test for side effects in a single game first.
- If you prefer a clean driver footprint, perform an express uninstall and then a fresh install; advanced users can use Display Driver Uninstaller (DDU) offline mode before installing a new driver.
For content creators and Premiere Pro users
- The 591.44 WHQL release contains a fix for an Adobe Premiere Pro freeze that could occur during hardware‑accelerated export on specific system configurations. If you experienced that freeze, installing 591.44 is recommended.
- However, a small subset of user reports from community forums showed isolated issues with hardware encoding immediately after the update — these reports were not universal, and some users successfully exported with the Studio variant of the driver. If you rely on stable render pipelines for production, test a short export before committing to a long batch job and keep the previous driver installer available for rollback.
General precautions
- Always verify the driver package you download by matching checksums where available.
- For mission‑critical machines, stagger deployment and validate with a set of representative workloads before rolling out widely.
- If you rely on older hardware that has reached end‑of‑life for a given driver branch (for example, specific GTX 10/900 series cards were noted as nearing or ending mainstream support), plan for longer‑term hardware lifecycle decisions.
Strengths of Nvidia’s response
- Speed: The hotfix was rapid and pragmatic — Nvidia prioritized delivering a quick mitigation before a full WHQL pass.
- Integration into WHQL: Folding the hotfix into the stable 591.44 WHQL release ensures broader distribution and increased confidence in the fix.
- Legacy support attention: Re‑enabling 32‑bit PhysX for select classic games addresses an important cultural and practical need in PC gaming, where long‑tail support matters to many players.
- Wide scope of fixes: The 591.44 release addresses both gaming and content‑creation pain points, which benefits gamers and creators.
Risks, limitations, and caveats
- Hotfix QA trade‑offs: The initial hotfix was shipped with an abbreviated QA cycle by design. While 591.44 is WHQL certified, hotfixes' limited testing can still leave rare regressions that require follow‑ups.
- Not a universal cure: The regression was not identical across all systems. Some configurations saw little change after the update and therefore receive little benefit from the driver beyond other bug fixes.
- Potential for new regressions: Any driver update can introduce regressions. Community threads show isolated reports post‑591.44 where features like hardware encoding behaved unexpectedly on some machine configurations. Those instances appear to be the exception rather than the rule, but production users should validate before mass deployment.
- PhysX scope is limited: The 32‑bit PhysX re‑enablement is selective. Expect a curated games list rather than a blanket restoration across every legacy PhysX title.
- Longer‑term deprecation: The re‑enablement is a practical concession rather than a reversal of the broader shift away from 32‑bit CUDA support on newer architectures. Developers and the platform ecosystem continue moving toward 64‑bit, and long‑term reliance on restored 32‑bit paths is not guaranteed.
How vendors and users can reduce future risk
- Microsoft and GPU vendors should continue to expand collaborative telemetry pathways so cross‑vendor regressions are detected and triaged faster.
- Hardware vendors and game/creative software makers should expose reproducible test cases that make it easier to identify API or scheduler interactions causing regressions.
- Users can reduce exposure to surprise regressions by:
- Staggering major OS updates on production machines.
- Applying updates first to a test bench or non‑critical system.
- Keeping fallback images or drivers on hand for quick rollback.
Final verdict
GeForce Game Ready Driver 591.44 WHQL is a necessary, well‑timed update for Windows 11 users who experienced reduced gaming performance after Microsoft’s October 2025 update, and it sensibly absorbs the earlier hotfix into a fully certified driver package. The release also delivers welcome side benefits: targeted game stability and performance fixes, a notable creative‑app regression fix for Adobe Premiere Pro exports, and a pragmatic restoration of 32‑bit PhysX GPU acceleration for a select set of legacy titles on the RTX 50‑series.For the typical enthusiast or creator who encountered the KB5066835‑related slowdown, installing 591.44 is the right move. For users who didn’t see regressions and whose workflows are sensitive to even minor changes, a short delay and routine verification is a prudent approach. In every case, the incident underscores a larger truth: the PC ecosystem’s complexity means single OS updates can interact unpredictably with device drivers, but vendor responsiveness, combined with conservative deployment strategies by users and admins, can blunt the fallout.
In short: if your system felt the hit after October’s Windows update, install GeForce Game Ready Driver 591.44 WHQL to regain performance, validate your most important workloads after installation, and keep an eye on driver notes and community reports for any follow‑up fixes or adjustments.
Source: eTeknix Nvidia Game Ready 591.44 Driver Restores Lost Performance in Windows 11
