EnablePrefetcher and EnableSuperfetch: registry values, defaults and gaming
Short answer
UpdatedPrefetch records what a program loads when it starts so the next start is faster, and Superfetch preloads what you use often. EnablePrefetcher and EnableSuperfetch set to 0 switch both off in the memory manager, separately from the SysMain service. In the registry it sets EnablePrefetcher to 0 under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters, and 1 more value.
HKLMSYSTEM\
EnablePrefetcher30
What it does
Prefetch records what a program loads when it starts so the next start is faster, and Superfetch preloads what you use often. EnablePrefetcher and EnableSuperfetch set to 0 switch both off in the memory manager, separately from the SysMain service.
In the app the switch is called "Disable Prefetcher/Superfetch (Reg)", described there as: Stops prefetch traces even if SysMain is re-enabled.
When it helps, and when it hurts
When it helps
- Systems where the prefetch work itself causes disk activity at bad moments, mostly on hard disks under memory pressure.
When it hurts
- Programs and Windows itself can start more slowly, because nothing is preloaded.
- On an SSD with enough memory the prefetcher costs next to nothing, so there is little to win.
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\ | 0 | 3 |
| HKLMSYSTEM\ | 0 | 3 |
From the app's source (prefetch_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\PrefetchParameters" /v "EnablePrefetcher" /t REG_DWORD /d 0 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters" /v "EnableSuperfetch" /t REG_DWORD /d 0 /freg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters" /v "EnablePrefetcher" /t REG_DWORD /d 3 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters" /v "EnableSuperfetch" /t REG_DWORD /d 3 /freg query "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters" /v "EnablePrefetcher"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 EnablePrefetcher back to 3, EnableSuperfetch back to 3.
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
Mostly folklore on modern hardware. Leave it on unless you measured a problem.
Questions
- What does the "Disable Prefetcher/Superfetch (Reg)" tweak change in Windows?
- In the registry it sets EnablePrefetcher to 0 under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters, 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 EnablePrefetcher?
- Frozen Tweaks writes 3 when you switch the tweak off, which is the value it treats as the Windows standard. With the tweak on, EnablePrefetcher is 0.
- Is "Disable Prefetcher/Superfetch (Reg)" safe to switch on?
- Mostly folklore on modern hardware. Leave it on unless you measured a problem. The main cost: Programs and Windows itself can start more slowly, because nothing is preloaded.
- 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.
- Is "Disable Prefetcher/Superfetch (Reg)" 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 Prefetcher/Superfetch (Reg)
- Category
- Clean
- Plan
- Pro
- Undo
- Yes
Related guides
- Windows 11 Gaming Optimization: What Still Works in 2026An honest audit of Windows 11 gaming tweaks: which settings still measurably help in 2026, which are placebo, and which quietly cost you security.8 min read
- What Is Safe to Delete on a Gaming PC, and What to Leave AloneTemporary files, update leftovers, crash dumps and caches can go. Shader caches cost you stutter once. Here is the list, and what a cleaner should never touch.4 min read
More tweak explainers
- Distributed Link Tracking Client (TrkWks)TrkWks keeps shortcuts and links working when the file they point to is moved to another NTFS drive or computer in a domain. What it changes and how to undo it.2 min read
- Scheduled drive optimizationWindows runs a weekly task that defragments hard disks and sends TRIM to SSDs, and Storage Sense has its own cleanup task. What it changes and how to undo it.2 min read
- NTFS last access and 8.3 namesNTFS can record when each file was last read and keep a short DOS-style name (PROGRA~1) for every file. What it changes, when it hurts, and how to undo it.3 min read
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
- Clean
- 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.