An hour of screen recording is a lot of gigabytes by default
Capture tools favour quality and write speed over size. Where the files go, and the settings that halve them.
A screen recording is the largest thing most PCs produce. The defaults favour quality and reliable writing over file size, which is right while recording and expensive afterwards, because nobody revisits those settings.
Where recordings land
Get-ChildItem "$env:USERPROFILE\Videos" -Recurse -Include *.mkv,*.mp4,*.mov -File -EA SilentlyContinue |
Sort-Object Length -Descending | Select-Object -First 15 @{n='MB';e={[math]::Round($_.Length/1MB)}}, FullNameOBS writes to whatever output path is set, defaulting to Videos. Windows' own Game Bar writes to Videos\Captures, which is a folder plenty of people have never opened and which fills quietly if the background recording feature is on.
The Game Bar one people do not know about
Xbox Game Bar has a background recording option that keeps the last few minutes continuously so you can save a clip after something happens. It writes constantly while it is on. Settings, Gaming, Captures is where it lives, along with a limit on how much it may keep.
The settings that matter in OBS
| Setting | Default effect | Better for size |
|---|---|---|
| Encoder | Often software x264 | The GPU hardware encoder |
| Rate control | CBR at a high bitrate | CQP or CRF, quality based |
| Resolution | Full display, often 4K | Downscale to what you publish |
| Recording format | MKV, safe against crashes | Keep, then remux to MP4 |
| Replay buffer | Holds minutes in memory and on disk | Off unless you use it |
The hardware encoder is the single change worth making: a much smaller file for the same visual quality, and less load while recording.
Remuxing rather than re-encoding
Recording to MKV protects you from a crash, because the file stays playable. Remuxing to MP4 rewrites the container without touching the video, so it is fast and lossless. It does not reduce the size; that comes from the encoder settings.
The habit
Keep the export, not the raw capture, unless you will genuinely re-edit. Move anything worth keeping off the system drive. Video is near the top of the order for a full C drive for exactly this reason.
Common questions
Where does OBS save recordings on Windows?
In the output path set in its settings, which defaults to the Videos folder. Windows' own Game Bar saves separately to Videos\Captures.
How do I make screen recordings smaller?
Use the GPU hardware encoder rather than software x264, switch to quality based rate control, and downscale to the resolution you actually publish at.
What is the Captures folder in Videos?
Where Xbox Game Bar saves clips and screenshots. Its background recording option writes continuously while enabled, which fills the folder quietly. Settings, Gaming, Captures controls it.
Should I record to MKV or MP4?
MKV is safer against a crash because it stays playable, then remux to MP4 afterwards. Remuxing rewrites the container without re-encoding, so it is fast and loses nothing.