What Is a Replay Buffer? (And Why Every Gamer Needs One)
The worst feeling in gaming
You just pulled off the play of your life. A 1v5 clutch. A last-second redirect goal. A frame-perfect parry into a full combo. Your hands are shaking. Your friends in Discord are screaming.
And you weren't recording.
This has happened to literally every PC gamer. The best moments are always the ones you didn't expect, which means they're the ones you weren't prepared to record. Manual recording doesn't work because you'd need to predict the future.
A replay buffer solves this permanently.
How a replay buffer works
A replay buffer is always recording, but it never saves anything until you tell it to. Think of it like a dashcam for your gameplay.
Here's the technical version in plain English:
Your game is running and your GPU is rendering frames. A replay buffer captures those frames and encodes them into a rolling video buffer in memory (RAM). The buffer holds the last X seconds — let's say 20 seconds. Every new frame pushes out the oldest frame. It's a loop.
When you press your hotkey, the buffer dumps its contents to a video file on your drive. That's your clip. Everything that happened before you pressed the button is already in the buffer.
If you never press the button? Nothing gets saved. No giant files, no wasted storage.
Replay buffer vs. manual recording
With manual recording, you press "record" before you start playing. You end up with a 45-minute file that's 98% walking between bombsites and buying weapons. Finding the one good moment means scrubbing through the entire video.
With a replay buffer, you press a button AFTER something happens. You get a 15-20 second file of exactly the moment that mattered. No scrubbing, no giant files, instant access.
The storage difference is massive too. A 45-minute Valorant session recorded manually at 1080p 60fps produces a file around 4-6 GB. Twenty replay buffer clips from that same session? About 600 MB total. And each one is a highlight, not a haystack.
How to set it up in Replayd
Replayd has replay buffer enabled by default. You don't need to configure anything. Launch the app, launch your game, and it starts automatically.
If you want to customize it:
Buffer length — How many seconds the buffer holds. Default is 15 seconds. Range is 5 to 30 seconds. Longer buffer = longer clips but slightly more RAM usage (a 30-second buffer uses roughly 200-400 MB of RAM depending on resolution).
Hotkey — Default is Alt+F. Press this when something happens and the buffer writes to disk. Pick something you can hit without thinking. Mouse side buttons work great for this.
Resolution and FPS — Default is 1080p 60fps. This is the sweet spot for most people. Higher resolution or FPS uses more encoder bandwidth but the impact is still minimal since it's all hardware-encoded.
What buffer length should you use?
This depends entirely on what game you're playing and how long the moments you want to capture tend to last.
Fast-paced shooters (Valorant, CS2, R6 Siege)
15 seconds — Kills happen fast. An ace in Valorant is usually 5-10 seconds. A 1v3 clutch might be 12 seconds. 15 seconds gives you enough lead-in to see the setup without the clip being mostly dead time.
Movement shooters and BRs (Apex Legends, Fortnite, Warzone)
20-25 seconds — Fights last longer in these games because of healing, building, and repositioning. A full squad wipe in Apex can easily take 15-20 seconds.
MOBAs (League of Legends, Dota 2)
25-30 seconds — Team fights start with picks and positioning before the actual brawl. You want to capture the initiation and the fight, not just the cleanup kills.
Rocket League
10-15 seconds — Goals are fast. Unless you're chaining passes across the field, 15 seconds captures the full play with room to spare.
Open world / RPGs (Elden Ring, Souls games)
20-25 seconds — Boss fight moments can have a long wind-up before the payoff. A close dodge into a punish into a kill might span 20 seconds.
Racing games (Forza, iRacing)
15-20 seconds — Overtakes and crashes are quick, but you want enough lead-in to show the approach.
How much storage do clips actually use?
At 1080p 60fps, replay buffer clips are small:
- 10-second clip: ~20-30 MB
- 15-second clip: ~30-50 MB
- 20-second clip: ~40-65 MB
- 30-second clip: ~60-100 MB
The exact size depends on the game. Games with lots of fast movement (Apex, Fortnite) produce larger files than games with static cameras (League of Legends, Chess). This is because video compression works better when less changes between frames.
At these sizes, you could store over 1,000 clips on 50 GB of drive space. That's probably more clips than you'll save in a year.
Replayd saves clips to ~/Videos/Replayd/ by default. You can change this in Settings if you want clips on a different drive.
Why GPU encoding makes this possible
The reason replay buffers can run with near-zero performance impact is hardware encoding. Your GPU has a dedicated chip — NVENC (NVIDIA), AMF (AMD), or QuickSync (Intel) — designed specifically for encoding video. It operates independently from the cores that render your game.
Without hardware encoding, a replay buffer would need your CPU to compress every frame in real-time. That would genuinely hurt your game's performance. With hardware encoding, the only CPU cost is copying the captured frame to the encoder, which is negligible.
This is also why replay buffers barely affect FPS even at 1080p 60fps. The encoder chip has the bandwidth to handle it without breaking a sweat.
Set it and forget it
The whole point of a replay buffer is that you never think about it. Set it up once, pick your buffer length, and play your games. When something worth saving happens — and it will — you press one button and it's saved.
No planning, no giant files, no missed moments.
Download Replayd — replay buffer is on by default. Just install and play.