Disable Nagle's Algorithm (TCP Send Delay)

What it changes

Tells the TCP stack to send small packets immediately instead of batching them, and to acknowledge every packet instead of every other one, on every network interface.

Why it helps

• A TCP-based real-time app that does not set TCP_NODELAY itself can see up to 200 ms of extra delay from Nagle plus delayed ACK.

Trade-offs

• Real-time multiplayer games overwhelmingly use UDP for latency-sensitive traffic precisely to avoid this, and TCP in a modern game is usually matchmaking, chat, and patching. Expect no change in most games, which is why this is opt-in.
• Slightly more packets on the wire for bulk TCP transfers.
• Applies to every interface present now; an adapter added later (a VPN, a new NIC) is not covered until you apply again, and the badge shows STANDARD until every adapter has the values.
• The values are read when an interface binds, so a restart (or disabling and re-enabling the adapter) is needed.

Requires administrator rights and a restart.

Details

• Sets TcpAckFrequency=1 and TCPNoDelay=1 under every interface key below HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces. Revert deletes both values, which is the Windows default.

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Part of Performance Tweaks. This page is the same text as the app's Learn more button, generated from Help/tweaks/nagle_disable.md. To fix something, edit that file (or open an issue); wiki edits are overwritten on the next sync.