Memory tweaks

What this section changes

Shared svchost processes for Windows services: less memory, but one crash can take down several and Task Manager loses per-service figures.

Applying it

1. Open w0a
2. Go to the Regedit Tweaks page in the left menu
3. Find this section and press Apply on the entries you want

Every entry has its own button, so you are not required to apply a whole section — Apply All at the top of the page is there for when you do want all of them.

Undoing it

Two ways, both of which work:

• Backups & Restore — puts back the checkpoint written before the change was applied. It

puts back everything applied after that point, later checkpoints included — the confirmation says exactly that before it starts.

• The Fix page — searched by symptom, writes the Windows default unconditionally. It does not

read a backup, so it works even if w0a's own backup file is gone.

The undo log lives at %ProgramData%\w0a\backup.json, outside your user profile.

The risk

Everything here is a documented value Windows supports; none of it is kernel-level and none of it is irreversible. The honest sentence is still this: a setting may have no measurable benefit for you. If you apply a change and feel no difference, you are probably right — these pages are not selling you a feeling, they are telling you what was changed.

If you want to measure it, the rule from reading the benchmark applies: change one thing at a time, and read the lows rather than the average.

First, the honest sentence

This section holds one setting, and what it changes is how many svchost.exe processes your Windows services run in. It does not add memory, make memory faster or touch the paging file. How much memory it saves on your PC, and whether that shows in a game, has not been measured. The reason it exists is Microsoft's own: its page on service host grouping says that giving each service its own process increases memory use. That matters most where memory is short, which is why the page shows a note about it only on machines with less than 8 GB of RAM.

Box by box

Consolidate service processes (svchost) — writes SvcHostSplitThresholdInKB = 0xFFFFFFFF (4294967295) as a DWORD under HKLM\SYSTEM\CurrentControlSet\Control. Since Windows 10 version 1703, Windows gives nearly every service its own svchost.exe once installed RAM is above about 3.5 GB; the service manager groups services into shared processes only while installed RAM, counted in KB, is below this value. 0xFFFFFFFF KB is 4 TiB, above any real machine, so grouping always applies. Windows' own value, the one the Fix page writes back, is 3670016: 3.5 GB in KB. It takes effect after a restart. On builds older than 15063 (Windows 10 1703) nothing is written: services there are already grouped, and the card says so instead of reporting a change. The trade, which the page states as well: services that share a process share its fate, so one service crashing can take the others in its process down with it, and Task Manager can no longer show per-service figures.

How to check it yourself

reg query "HKLM\SYSTEM\CurrentControlSet\Control" /v SvcHostSplitThresholdInKB

After the box has run the value is 0xFFFFFFFF; after the Fix card it is 3670016 (0x380000). To see the grouping itself, list each svchost.exe with the services it hosts, and compare the list from before the restart with the one after:

tasklist /svc /fi "imagename eq svchost.exe"

What this section does not do

It does not size the threshold to your RAM. An earlier build wrote a fixed 0x4000000 — 64 GiB — and on machines with 64 GB or more that was not above installed RAM, so services kept splitting while the card reported success. That is why the value is now the largest a DWORD can hold.

It never writes DisablePagingExecutive, LargeSystemCache, DisablePageCombining or NtfsMemoryUsage. The first three belong to the kernel's memory manager and the fourth sizes the NTFS driver's paged pool; w0a writes no kernel-level value at all. If an older build or another tool left DisablePagingExecutive, DisablePageCombining or NtfsMemoryUsage behind, the Memory and system defaults card on the Fix page deletes them.

Outside this page

The Memory and system defaults card on the Fix page writes 3670016 back (Memory and system defaults). In the same press it also returns other memory, file system and scheduler values to the Windows default, and asks for a restart. The disk guide explains what one process per service shows you in Task Manager, and so what this setting takes away (Disk at 100% in Task Manager).