The best moments on stream happen when you least expect them, and by the time you think “I should clip that,” it is already gone. The OBS Replay Buffer solves this by continuously holding the last chunk of your stream in memory, so a single hotkey saves the previous 30 seconds to a file. Set it up once and you will never lose a clutch play or a perfect reaction again.
What the replay buffer actually does
The Replay Buffer records constantly into RAM in a rolling window — say the last 30 seconds — without writing anything to disk. When you hit the save hotkey, OBS dumps that window to a video file instantly. Because it lives in memory, it costs a little RAM but adds almost no extra CPU beyond normal recording, and it works whether or not you are also recording locally.
Step 1: Enable it in settings
Open Settings, go to Output, and switch to Advanced output mode. Under the Replay Buffer tab, check Enable Replay Buffer and set the maximum replay time. Thirty seconds suits most highlights; 60 seconds is handy for longer sequences but uses more RAM.
| Setting | Recommended | Impact |
|---|---|---|
| Max replay time | 30–60 sec | Longer = more RAM used |
| Encoder | NVENC / hardware | Frees CPU for the game |
| Recording quality | High (CQP ~18–20) | Clean clips, larger files |
| Format | MP4 or MKV | MP4 shares easily |
Step 2: Estimate the RAM cost
OBS shows an estimated memory requirement based on your bitrate and buffer length. A 30-second 1080p60 buffer at a high quality setting typically needs a few hundred megabytes of RAM — trivial on a 16GB or 32GB system. If the estimate looks large, shorten the buffer or lower the recording bitrate.
Step 3: Assign hotkeys
Go to Settings, Hotkeys, and bind two actions: Start Replay Buffer and Save Replay. Bind Save Replay to something you can hit reflexively without looking — a spare mouse button or a Stream Deck key is ideal so you can save a moment mid-fight. Remember the buffer must be started (there is a button in the Controls dock) before it can save anything.
Step 4: Set where clips save
Point the recording path to a fast drive with room to spare, ideally an SSD so writes never hitch during a game. Name your clips with a timestamp so a highlight-hunting session later is easy to sort. Many streamers dump replays into a dedicated folder they scrub through after each stream for shorts and social posts.
Turning saved replays into content
The replay buffer is only half the workflow; the other half is doing something with the clips. Build a habit of scrubbing your replay folder after each stream, trimming the best 15–30 second moments, and exporting them vertically for shorts and reels. Because the buffer already saved a high-quality file at the moment it happened, you skip re-encoding a long VOD to hunt for highlights. Name clips with the game and a quick tag as you save them so sorting later takes seconds. A steady stream of clipped moments feeds your discovery on TikTok, YouTube Shorts, and Reels, which is often where new viewers find a channel in the first place.
FAQ
Does the replay buffer hurt my stream performance?
Barely, if you use hardware encoding like NVENC. It reuses your existing encode and holds the result in RAM, so the extra cost is memory plus a brief disk write when you save. Keep it on a hardware encoder and a mid-range or better GPU handles it without dropped frames.
Why did my save hotkey do nothing?
The Replay Buffer has to be running first. Click Start Replay Buffer in the Controls dock (or bind and press the start hotkey) at the beginning of your stream. If it is not started, the save hotkey has no rolling window to write.
Bottom line
Enable the Replay Buffer in Advanced output, set a 30–60 second window on a hardware encoder, bind Save Replay to a reflex-friendly button, and start the buffer at the top of every stream. It is nearly free in performance and turns “I wish I’d clipped that” into a habit that feeds your highlights and shorts pipeline automatically.
