What Virtualization-Based Security Is and Why It Slows Old PCs
Virtualization-Based Security in Windows is a set of protection features that run parts of the operating system inside an isolated virtual environment, adding an extra security layer that can significantly increase system resource usage on older PCs and make them feel much slower than their hardware alone would suggest. VBS uses the Windows hypervisor to create Virtual Secure Mode, a protected memory area that sits between your apps and the hardware. Every low-level security check—such as validating driver signatures or reading secure credentials—requires a costly context switch known as a hyper-exit. On modern CPUs this overhead is often masked by hardware acceleration, but many 6th and 7th gen Intel Core processors fall back to software emulation instead. That emulation demands constant CPU time, so your legacy desktop ends up spending more effort on security bookkeeping than on the work you actually care about.
Core Isolation and Memory Integrity: The Main Culprits
Within Windows’ Virtualization-Based Security stack, Core Isolation and its Memory Integrity option are the features most likely to hurt performance on aging systems. Memory Integrity runs kernel-level drivers in a virtualized, protected space and scans them in the background for tampering. According to MakeUseOf, this is the layer that can “eat up a lot of processing cycles that older quad-core chips can’t spare,” especially when hardware virtualization support is limited. The effect is a constant drag: your CPU is interrupted frequently for security checks it cannot handle efficiently, so basic tasks like opening apps or switching browser tabs feel slow. The trade-off is clear: you gain protection against advanced kernel-level malware at the cost of everyday responsiveness. For many people trying to keep an older PC usable, selectively turning off Memory Integrity is a practical Windows performance optimization and a realistic slow PC fix.
How to Safely Disable Memory Integrity on Windows
Before you change anything, make sure you have another security layer in place, such as a reputable antivirus, and that Windows Update is working. Then open the Start menu, type “Windows Security,” and launch the app with the shield icon. In the sidebar, select Device Security. Under Core isolation, click Core isolation details. You will see a toggle for Memory Integrity. Turn this off, approve the User Account Control prompt, and restart your PC so Windows can remove the virtualization layer from low-level drivers. After reboot, Windows Security may show a yellow warning triangle to highlight that a recommended feature is disabled. That notification is expected, not an emergency. Use your PC for a while and watch CPU and memory usage; many users notice that their system no longer feels like it is “crawling” once this background overhead is removed.
Use Task Manager’s Details Tab to Confirm the Slowdown Is Gone
After disabling Memory Integrity, verify that your performance issues are reduced rather than guessing. Press Ctrl + Shift + Esc to open Task Manager, then switch to the Details tab. Here you can add detailed columns and see how Windows is using system resources over time. Right-click a column header, choose Select columns, and enable CPU time to see which processes have consumed the most processor seconds since startup. MakeUseOf highlights that CPU time is ideal for spotting services that spike the CPU in short bursts, such as security tools running frequent scans. Also pay attention to memory-related columns like Working set (memory) and Peak working set to ensure no process is leaking RAM and causing secondary slowdowns. If, after the change, CPU time and working sets look more reasonable and your system feels smoother, you have confirmed a successful Windows security disable for performance.
What to Keep Enabled and When Not to Disable Security
Disabling Memory Integrity does not mean you should turn off every security feature. Keep real-time antivirus, firewall protection, and regular Windows updates enabled, since they protect you against common threats with far less impact on older hardware. Avoid disabling security if your PC handles sensitive work data, if you regularly install unsigned drivers or apps from untrusted sources, or if you already suspect malware infection. In those cases, the stricter isolation is worth the overhead. Treat this change as a targeted Windows performance optimization for specific legacy systems that feel borderline unusable in daily tasks. If you make the switch, compensate with safe habits: download software from trusted sites, keep backups, and scan new files before opening them. Balancing system resource usage against realistic risk will help you keep an aging PC responsive without giving up essential protection.