this post was submitted on 28 Sep 2025
44 points (100.0% liked)
Linux Gaming
23097 readers
71 users here now
Discussions and news about gaming on the GNU/Linux family of operating systems (including the Steam Deck). Potentially a $HOME away from home for disgruntled /r/linux_gaming denizens of the redditarian demesne.
This page can be subscribed to via RSS.
Original /r/linux_gaming pengwing by uoou.
No memes/shitposts/low-effort posts, please.
Resources
WWW:
- Linux Gaming wiki
- Gaming on Linux
- ProtonDB
- Lutris
- PCGamingWiki
- LibreGameWiki
- Boiling Steam
- Phoronix
- Linux VR Adventures
Discord:
IRC:
Matrix:
Telegram:
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Input lag is caused by frame interpolation, right? Or nah?
It's because game logic is calculated on real frames and these things lower the real frame rate even though they give you more rendered frames. If you were getting 40 real FPS, and then you go to 30 real fps, you will feel a significant amount of lag even if you are getting 60 fps in fake frames. Basically the game loop is running slower and stuff like input polling is happening slower even if you have a higher frame rate.
Frame generation shouldn't be a bottleneck on the CPU though, should it? That stuff is happening on the GPU. I know I saw a video about this stuff but I can't remember the real reason input lag increases with frame generation/interpolation.
Most games aren't bottlenecked by your CPU at all. It spends a lot of time waiting for the GPU to be done drawing you a picture.
"Why isn't the game doing other stuff meanwhile?" you might ask, and part of the answer is surely, "Why do stuff faster than the player can see?", while another part is likely a need to syncronize the simulation and the rendering so it doesn't show you some half-finished state, and a third part might be that it would be very confusing for the player to decouple the game state from what they see on screen, like you see yourself aiming at the monster, but actually it moved in between frames so your shot will miss even if the crosshair is dead on.
I didn't mean the game loop being bottlenecked, I said frame generation. But yeah, all that is also true, I know. 👍
I was trying to explain why the game loop would be held back by the rendering speed, even though they run on different hardware.
If you are bottlenecked by the GPU that means the game loop spends some of its time waiting for the GPU. If you then turn on frame generation, you devote parts of the GPU to doing that, which makes regular rendering slower, making the game loop spend even more time waiting. This will increase input latency.
Frame generation also needs to delay output of any real frame while it creates and inserts a generated frame. This will add some output latency as well.
In the opposite scenario, where you are bottlenecked by the CPU, enabling frame generation should in theory not impact the game loop at all. In that case it's the GPU that's waiting for the CPU, and it can use some of those extra resources it has to do frame generation with no impact on input latency.