Windows Defender impact on gaming: how much FPS it actually costs

Windows Defender runs real-time file scanning. Every file your game reads gets checked. For a game streaming assets from disk, this adds overhead.

How much it costs

Benchmarks vary by game. In open world games with heavy streaming (RDR2, GTA V, large modpacks): 5-15% CPU overhead is realistic. In arenas or closed maps: 2-5%.

The right approach: exclusions, not disabling

Disabling Defender entirely is a security trade-off most people shouldn't make. Adding game folder exclusions eliminates the overhead without the exposure:

1. Windows Security → Virus & threat protection → Manage settings → Exclusions
2. Add folder: your Steam library folder (e.g. D:\SteamLibrary)
3. Add folder: your game install directories
4. Add process: steam.exe, EpicGamesLauncher.exe

This tells Defender to skip scanning these locations entirely.

Process exclusions

Adding the game executable as a process exclusion stops Defender from scanning files that the game process opens:

Add-MpPreference -ExclusionProcess "cs2.exe"
Add-MpPreference -ExclusionProcess "r5apex.exe"
Add-MpPreference -ExclusionProcess "FiveM.exe"

Scan scheduling

Defender scheduled scans default to running during "low activity" periods — which sometimes means while you're gaming. Reschedule them to specific off-peak times.

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