Microsoft: Windows 11 BitLocker can slow fast NVMe PCs in gaming/video editing. Historically single-digit overhead

By Admin

25 Dec, 2025

Introduction
Microsoft has officially acknowledged that enabling BitLocker on Windows 11 systems equipped with high-speed NVMe SSDs can introduce a noticeable performance impact in certain scenarios. While BitLocker has historically added only a single-digit percentage overhead in most cases, modern hardware and recent Windows changes have brought renewed attention to its performance implications especially for gamers, developers, and video editors using fast NVMe storage.

Why BitLocker Matters More in Windows 11
BitLocker was once an optional feature that many users chose to enable only when data security was a priority. However, with the release of Windows 11 version 24H2, Microsoft made BitLocker a default feature on newer PCs and clean installations. Users upgrading from Windows 11 23H2 to 24H2 are not automatically enrolled, but new systems now ship with BitLocker turned on by default.

Microsoft emphasizes that BitLocker remains a valuable security feature. If a device is lost or stolen, BitLocker encrypts the drive and ensures sensitive data cannot be accessed without proper authentication. The concern is not about security, but about balancing security with performance on modern hardware.

Does BitLocker Affect Windows 11 Performance?
According to Microsoft, BitLocker does come with a performance cost, particularly on newer NVMe SSDs capable of extremely high input/output operations per second (IOPS). These drives can process data so quickly that the CPU must work harder to keep up with BitLocker’s real-time encryption and decryption using AES (Advanced Encryption Standard).

Historically, BitLocker’s overhead was limited to single-digit percentages in most workloads. However, as NVMe drives have become significantly faster, the encryption workload has shifted from being negligible to more noticeable, especially during heavy I/O operations.

Why NVMe Drives Make the Impact More Visible
Modern NVMe SSDs deliver exceptionally high throughput and random I/O performance. While this is excellent for system responsiveness and application speed, it also means that the CPU must handle a larger volume of encryption and decryption tasks per second when BitLocker is enabled.

Microsoft explains that as I/O per second increases, the CPU spends a higher proportion of its cycles performing cryptographic operations. If this process is not properly optimized, it can become a bottleneck in performance-intensive scenarios.

Scenarios Where You May Notice Higher CPU Usage
Users are more likely to see the impact of BitLocker on performance when performing drive-intensive tasks such as:

• Playing modern PC games that constantly stream assets from disk
  
  

• Compiling large codebases or software projects
  
  

• Editing or rendering large video files
  
  

• Any workload involving frequent small file reads and writes
  
  

In these situations, increased CPU usage can translate into lower frame rates, slower processing times, or reduced overall responsiveness.

Microsoft’s Solution: Hardware-Accelerated BitLocker
To address these concerns, Microsoft has introduced hardware-accelerated BitLocker in newer Windows 11 builds, starting with updates such as Windows 11 KB5065426 (26100.6584 / 26200.6584) and later.

With hardware acceleration enabled, cryptographic operations are offloaded from the CPU to a dedicated crypto engine built into the system-on-chip (SoC) or CPU. Encryption keys can also be protected at the hardware level, improving both performance and security.

Microsoft states that this approach significantly reduces CPU overhead and improves battery life, particularly on laptops. Early internal testing showed CPU cycle reductions of over 70% compared to software-based BitLocker.

Performance Comparison Using CrystalDiskMark
Microsoft shared CrystalDiskMark benchmark results comparing software-based BitLocker with hardware-accelerated BitLocker on two systems with identical hardware.

Sequential performance remains largely unchanged:

• Sequential read and write speeds showed negligible differences of around 0.6%
  
  

• Large file transfers are mostly unaffected by the encryption method
  
  

However, the biggest difference appears in random 4K workloads, which are critical for gaming and application responsiveness:

• Random 4K Q32T1 read and write performance was over 2.3 times faster with hardware acceleration
  
  

• Random 4K Q1T1 read performance improved by around 40%
  
  

• Random 4K Q1T1 write performance more than doubled
  
  

These results clearly show that while large file operations remain similar, hardware-accelerated BitLocker dramatically improves small file and random I/O performance.

Device A vs Device B Explained
Device A uses traditional software-based BitLocker with no hardware crypto offloading support. Device B uses the new hardware-accelerated BitLocker with encryption offloaded to dedicated hardware.

Both devices run Windows 11, use the same XTS-AES 256 encryption method, and have identical hardware specifications. The key difference lies in how encryption is handled by the CPU in Device A and by dedicated hardware in Device B.

Overall Impact on Windows 11 Performance
Microsoft confirms that Windows 11 still performs marginally better when BitLocker is completely disabled. However, with hardware-based BitLocker enabled, the performance cost becomes negligible for most users. In practical terms, this means users can enjoy strong data protection without sacrificing gaming performance, creative workflows, or system responsiveness.

How to Check If Your PC Supports Hardware-Accelerated BitLocker
You can verify whether your system is using software or hardware-based BitLocker by running the following command in an elevated Command Prompt:

manage-bde -status

If the encryption method shows XTS-AES 256 (Hardware accelerated), your system is taking advantage of the new capability. If it only shows XTS-AES 256, then software-based encryption is still in use.

Can You Manually Enable Hardware-Accelerated BitLocker?
Windows 11 does not provide a manual toggle to switch from software-based to hardware-based BitLocker. If your system meets the hardware requirements and you have installed Windows updates released after September 2025, hardware-accelerated BitLocker will be enabled automatically.

Users only need to verify the status using the manage-bde -status command.

Possible Hardware Requirements
Based on Microsoft’s guidance, hardware-accelerated BitLocker requires:

• An NVMe SSD
  
  

• A crypto offload-capable SoC or CPU platform with proper driver support
  
  

• Intel vPro devices with Intel Core Ultra Series 3 (Panther Lake) are the first confirmed platforms to support it, with other vendors expected to follow
  
  

Conclusion
Microsoft’s admission highlights an important shift in how modern storage performance interacts with security features. While BitLocker can impact performance on fast NVMe systems during heavy workloads, the effect is usually minimal and historically limited to single-digit percentages. With the introduction of hardware-accelerated BitLocker, Microsoft is effectively eliminating most performance concerns while maintaining strong data protection.

For users on supported hardware, BitLocker no longer needs to be a trade-off between security and speed. As newer CPUs and SoCs roll out, hardware-based encryption is set to become the standard, ensuring Windows 11 remains both secure and high-performing for demanding use cases like gaming and video editing.