LargeSystemCache 1: what it does, the default value, and whether it helps games
Short answer
UpdatedLargeSystemCache tells the Windows memory manager to favor the file system cache over the memory of running programs. It was designed for file servers. This tweak sets it to 1 and raises IoPageLockLimit. In the registry it sets LargeSystemCache to 1 under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management, and 1 more value.
HKLMSYSTEM\
LargeSystemCache01
What it does
LargeSystemCache tells the Windows memory manager to favor the file system cache over the memory of running programs. It was designed for file servers. This tweak sets it to 1 and raises IoPageLockLimit.
In the app the switch is called "Enable Large System Cache", described there as: Allocates more RAM for file-system caching to speed up game asset loading (16 GB+ recommended, reboot).
When it helps, and when it hurts
When it helps
- Loading large game files repeatedly on a PC with plenty of spare memory, where more of them stay cached.
When it hurts
- On a PC with 16 GB or less, favoring the cache can push a game's own memory out to the page file, which causes exactly the stutter you wanted to avoid.
- Microsoft documents the setting for servers. Some drivers have behaved badly with it in the past.
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\ | 1 | 0 |
| HKLMSYSTEM\ | 0x08000000 | 0 |
From the app's source (large_system_cache.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 "LargeSystemCache" /t REG_DWORD /d 1 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "IoPageLockLimit" /t REG_DWORD /d 0x08000000 /freg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "LargeSystemCache" /t REG_DWORD /d 0 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "IoPageLockLimit" /t REG_DWORD /d 0 /freg query "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "LargeSystemCache"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 LargeSystemCache back to 0, IoPageLockLimit 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
Marginal at best on a gaming PC, and a risk with little memory. Use it only with 32 GB or more, and measure.
Questions
- What does the "Enable Large System Cache" tweak change in Windows?
- In the registry it sets LargeSystemCache to 1 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 LargeSystemCache?
- Frozen Tweaks writes 0 when you switch the tweak off, which is the value it treats as the Windows standard. With the tweak on, LargeSystemCache is 1.
- Is "Enable Large System Cache" safe to switch on?
- Marginal at best on a gaming PC, and a risk with little memory. Use it only with 32 GB or more, and measure. The main cost: On a PC with 16 GB or less, favoring the cache can push a game's own memory out to the page file, which causes exactly the stutter you wanted to avoid.
- 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 "Enable Large System Cache" 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
- Enable Large System Cache
- Category
- Memory
- Plan
- Pro
- Undo
- Yes
Related guides
More tweak explainers
- DisablePagingExecutiveWindows may move parts of its own kernel and drivers to the page file when memory is short. What it changes, when it hurts, and how to undo it.3 min read
- Memory compressionWhat Disable-MMAgent -MemoryCompression (-mc) changes, why turning off memory compression helps some PCs and badly hurts others, and how to put it back.2 min read
- NVMe interrupt steeringAn NVMe drive raises an interrupt when a read or write finishes. What the tweak changes, when it helps, when it hurts and how to undo it.2 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
- Memory
- 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.