FeatureSettingsOverride 3: disabling Spectre and Meltdown mitigations for performance
Short answer
UpdatedThe Spectre and Meltdown mitigations are processor security fixes that cost some performance, mostly on older processors. FeatureSettingsOverride and FeatureSettingsOverrideMask set to 3 switch the main mitigations off. In the registry it sets FeatureSettingsOverride to 3 under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management, and 1 more value.
HKLMSYSTEM\
FeatureSettingsOverride03
What it does
The Spectre and Meltdown mitigations are processor security fixes that cost some performance, mostly on older processors. FeatureSettingsOverride and FeatureSettingsOverrideMask set to 3 switch the main mitigations off.
In the app the switch is called "Disable Spectre/Meltdown Mitigations", described there as: Removes kernel mitigations for raw performance (security trade-off, reboot).
When it helps, and when it hurts
When it helps
- Older Intel processors (roughly 2019 and before), where the mitigations have a measurable cost in processor-bound games.
When it hurts
- The PC is open to a known class of attacks again, including from websites.
- On recent processors the fixes are built into the hardware and the gain is close to zero.
- Some anti-cheat systems may object to missing mitigations.
What it writes
Exactly what the switch changes, read from the app's source. Switching it off is what the app writes when you turn the tweak off again.
| Key and value | With the tweak | Switching it off |
|---|---|---|
| HKLMSYSTEM\ | 3 | 0 |
| HKLMSYSTEM\ | 3 | 0 |
From the app's source (perf_mitigations_off.hpp), app 2.0.0, checked .
The same change by hand
You do not need the app for this one. These commands make the changes from the table above. Run them in a Command Prompt opened as administrator, and make a restore point first.
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "FeatureSettingsOverride" /t REG_DWORD /d 3 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "FeatureSettingsOverrideMask" /t REG_DWORD /d 3 /freg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "FeatureSettingsOverride" /t REG_DWORD /d 0 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "FeatureSettingsOverrideMask" /t REG_DWORD /d 0 /freg query "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "FeatureSettingsOverride"How to undo it
In the app: Yes
Switching it off sets a standard Windows value, which may not be exactly how you had it.
Switch the tweak off in Frozen Tweaks. It writes FeatureSettingsOverride back to 0, FeatureSettingsOverrideMask back to 0.
Changing several settings at once? The app's Make a restore point button, on every plan, makes a Windows restore point before you start.
Verdict
A security trade we would only consider on an old processor, on a PC used for games and nothing sensitive.
Questions
- What does the "Disable Spectre/Meltdown Mitigations" tweak change in Windows?
- In the registry it sets FeatureSettingsOverride to 3 under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management, and 1 more value. The full list is in the table on this page, read from the app's source.
- What is the standard value of FeatureSettingsOverride?
- Frozen Tweaks writes 0 when you switch the tweak off, which is the value it treats as the Windows standard. With the tweak on, FeatureSettingsOverride is 3.
- Is "Disable Spectre/Meltdown Mitigations" safe to switch on?
- A security trade we would only consider on an old processor, on a PC used for games and nothing sensitive. The main cost: The PC is open to a known class of attacks again, including from websites.
- How do I undo it?
- Switch the tweak off in Frozen Tweaks. Switching it off sets a standard Windows value, which may not be exactly how you had it.
- Does it need a restart?
- Yes, the change applies after a restart.
- Is "Disable Spectre/Meltdown Mitigations" free in Frozen Tweaks?
- It is part of Frozen Pro and Elite. You can also make the change by hand with the values on this page.
In the app
- Switch
- Disable Spectre/Meltdown Mitigations
- Category
- Security
- Plan
- Pro
- Undo
- Yes
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Written by
Frost LIVEFounder of Frozen Tweaks, based in Hamburg, Germany. Publishes settings guides for competitive games on his YouTube channel, Frost LIVE.
In the app
- Category
- Security
- Plan
- Pro
- Undo
- Yes
Frozen Tweaks
Free for Windows 10 and 11
58 tweaks free, each with an undo switch. Never edits game files.
v2.0.0 · 6.4 MB · Windows 10 and 11, 64-bit · free account, no payment details
Or type frozentweaks.com on your PC.
The free Windows app for competitive games.
58 tweaks free, each with an undo switch. Never edits game files.
v2.0.0 · 6.4 MB · Windows 10 and 11, 64-bit · free account, no payment details
Frozen Tweaks runs on Windows. Send the link to your PC and download it there.
Or type frozentweaks.com on your PC.