Windows 11 Memory Integrity Is Turning On By Default — Here’s What Changes on Your PC

Memory Integrity is the friendlier name for Hypervisor-Protected Code Integrity, or HVCI. It uses your processor’s built-in virtualization hardware to wall off a small, isolated chunk of memory where Windows checks every kernel-mode driver before letting it run.

Think of it as a bouncer for the deepest, most trusted layer of your operating system. Drivers operate with almost total control over your PC, so a bad one — malicious or just poorly written — can crash the system or open a door for attackers. Memory Integrity forces every driver through that isolated checkpoint first.

Microsoft’s stated reason is blunt: kernel-level attacks are getting easier to pull off. Security researchers now use AI-assisted tools to hunt for vulnerable or unsigned drivers, and the pace of discovery has outstripped how fast individual bugs can get patched one at a time.

Memory Integrity sidesteps that arms race by blocking the exploitation method itself, not each individual flaw. It’s the same logic Microsoft used when it rolled out Administrator Protection to cut down on privilege-escalation attacks, and part of a broader push that also includes the post-quantum encryption work Microsoft is building into Windows 11.

Here’s the catch. Memory Integrity’s constant driver checks add a small amount of overhead, and in games that lean heavily on your CPU rather than your GPU, that overhead can show up as choppier frame rates.

How much you’ll notice depends almost entirely on your processor’s age. Newer chips have dedicated hardware for handling these virtualization checks efficiently, so the hit is small. Older CPUs fall back to slower software emulation, which is where gamers are most likely to feel it.

None of the outlets covering this rollout, including Tom’s Hardware and gHacks, have published hard benchmark numbers yet. Treat any specific percentage you see elsewhere online as a guess until real testing lands.

Microsoft isn’t flipping this switch for every Windows 11 PC at once. It only applies to machines that already meet a specific hardware bar, so plenty of older systems simply won’t see any change in October.

You don’t have to wait for October to see where you stand. Open Windows Security, go to Device security, then Core isolation, and you’ll see a clear On/Off toggle for Memory Integrity.

If it’s already on, nothing changes for you next month. If it’s off and you’re on eligible hardware, expect it to switch on after you install October’s cumulative update. You can always flip it back off from that same Core isolation screen if it causes a real problem, though Microsoft — and most security researchers — recommend leaving it alone unless you have a specific driver conflict.

It’s a security feature that isolates a check for every driver trying to run at the deepest level of Windows, blocking malicious or broken drivers before they can do damage.

It might, but mainly on older CPUs in games that are heavily CPU-bound. Newer processors handle the checks with hardware acceleration, so most recent gaming PCs should barely notice.

Go to Windows Security, then Device security, then Core isolation. The Memory Integrity toggle there shows whether it’s currently on or off.

Yes. Memory Integrity is the consumer-facing name Microsoft uses in Windows Security for Hypervisor-Protected Code Integrity, or HVCI.

If you manually disable it before October’s update installs, Microsoft’s auto-enable won’t override that choice. IT admins can also block it through Group Policy or Intune.

This is one of those rare Windows changes worth leaving alone. The security upside is real and the performance cost, based on everything reported so far, looks small and mostly limited to older hardware — so unless you’re chasing every last frame on an aging CPU, let Memory Integrity turn on and only reach for that Core isolation toggle if something actually breaks.