Delivery Optimization: stopping Windows using your upload for other people's updates

Frost LIVENetworkFreeUndo: YesUpdated Oct 8, 2026View as Markdown

Short answer

Updated Oct 8, 2026

Setting DODownloadMode to 0 under SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization restricts Windows Update to plain HTTP downloads and stops it sharing update files peer-to-peer with other machines. This is one of the few genuinely useful network tweaks, because the upload side can consume bandwidth and add jitter while you play.

In the app

Disable Delivery OptimizationFREE

Registry

HKLMSOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization

DODownloadModeNot set0

What the switch writes. Your current value may differ. 2 more changes below.

What it does

Delivery Optimization turns your PC into a peer that both downloads update content from, and uploads it to, other machines on your local network, and on the internet if that is allowed in Settings.

Upload saturation is a real cause of ping spikes, because a saturated upstream delays the acknowledgements your game is waiting on.

When it helps, and when it hurts

When it helps

Removes an unpredictable source of upstream bandwidth use, which is the kind that hurts latency most.
Useful on connections with limited upload, which describes most consumer connections.
Stops your machine serving update data to other PCs.

When it hurts

Updates may download more slowly, since they can no longer come from a nearby peer.
On a LAN with many Windows machines you lose a genuinely efficient distribution mechanism.

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.

Registry values the switch writes.
Key and value	With the tweak	Switching it off
HKLMSOFTWARE\Policies\Microsoft\Windows\DeliveryOptimizationDODownloadModeHTTP only: no peer-to-peer sharing, on the local network or the internet.	0	Not setThe value is deleted. Windows decides.
HKLMSOFTWARE\Policies\Microsoft\Windows\DeliveryOptimizationDOAbsoluteMaxCacheSizePctGives the Delivery Optimization cache no share of the disk.	0	Not setThe value is deleted. Windows decides.

Windows services the switch changes: their startup type.
Service	With the tweak	Switching it off
DoSvcDelivery OptimizationDownloads update content and shares it with other PCs. Set to Manual, Windows can still start it when an update needs it.	Disabled	Manual

From the app's source (delivery_optimization.hpp), app 2.0.0, checked Oct 8, 2026.

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.

Make the change · CMD

reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" /v "DODownloadMode" /t REG_DWORD /d 0 /f
reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" /v "DOAbsoluteMaxCacheSizePct" /t REG_DWORD /d 0 /f
sc config "DoSvc" start= disabled

Put it back · CMD

reg delete "HKLM\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" /v "DODownloadMode" /f
reg delete "HKLM\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" /v "DOAbsoluteMaxCacheSizePct" /f
sc config "DoSvc" start= demand

See what it is set to now · CMD

reg query "HKLM\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" /v "DODownloadMode"

How to undo it

In the app: Yes

Switching it off removes the Delivery Optimization policy values and sets the service to Manual, which Windows can still start when an update needs it.

Delete DODownloadMode and DOAbsoluteMaxCacheSizePct, then set DoSvc back to the start type it had before. Switching it off in Frozen Tweaks deletes both values and sets DoSvc to Manual; Windows can still start it when an update needs it.

Changing several settings at once? The app's Make a restore point button, on every plan, makes a Windows restore point before you start.