Very weird input/GPU lag at 99-100 gpu usage

[ko4]

I first noticed this in the game Warframe when I put all my settings on high. I Got decent fps in the 70-80 range.
when looking at stuff like grass the gpu usage reached 100 and when it does so, i get some weird input or gpu lag. its feels the same as lets say 75hz vsynced so lets say 13.33ms delay the ingame mouse also gets floaty. max pre rendered frames set to 1 in nvcp.
This is not higher input lag because of lower framerates. I confirmed this by capping fps lower than the max fps i can reach with 100 gpu usage. At lets say 85 gpu usage and still in the grassy area there is no input lag. This also happens in witcher 3 so it is not because of the warframe engine. Input lag when gpu gets bottlenecked. Input lag goes away when i cap fps so the gpu is not at 100%.
this is very weird, any ideas?

[RealNC]

This is normal. When the GPU is maxed out, you get an effect similar to uncapped vsync in many games. There's not much you can do about it. It also happens with vsync OFF, but also with g-sync or freesync. If the GPU becomes a bottleneck, input lag can pile up. The higher max prerendered frames is set to, the worse it gets.

To keep the problem to a minimum, use max prerendered frames 1. But you cannot completely eliminate the problem, unless you cap the FPS even lower to prevent the game from running uncapped.

In some cases, there might be a difference between setting in-game vsync to ON and nvcp vsync to "app controlled", and in-game vsync to OFF and nvcp vsync to ON. Try both and see if one is better than the other.

[ko4]

This is normal. When the GPU is maxed out, you get an effect similar to uncapped vsync in many games. There's not much you can do about it. It also happens with vsync OFF, but also with g-sync or freesync. If the GPU becomes a bottleneck, input lag can pile up. The higher max prerendered frames is set to, the worse it gets.

To keep the problem to a minimum, use max prerendered frames 1. But you cannot completely eliminate the problem, unless you cap the FPS even lower to prevent the game from running uncapped.

In some cases, there might be a difference between setting in-game vsync to ON and nvcp vsync to "app controlled", and in-game vsync to OFF and nvcp vsync to ON. Try both and see if one is better than the other.

Oh, thanks for explaining i was getting paranoid again. I was googling around looking around for an answer but i could find nothing about this. blurbusters is awesome

[ko4]

This is normal. When the GPU is maxed out, you get an effect similar to uncapped vsync in many games. There's not much you can do about it. It also happens with vsync OFF, but also with g-sync or freesync. If the GPU becomes a bottleneck, input lag can pile up. The higher max prerendered frames is set to, the worse it gets.

To keep the problem to a minimum, use max prerendered frames 1. But you cannot completely eliminate the problem, unless you cap the FPS even lower to prevent the game from running uncapped.

In some cases, there might be a difference between setting in-game vsync to ON and nvcp vsync to "app controlled", and in-game vsync to OFF and nvcp vsync to ON. Try both and see if one is better than the other.

Oh by the way, i forgot to mention that im not using any kind of sync no vsync no gsync. Is this still normal?

[RealNC]

Yes. Even without vsync, it's normal in many games. Some other games don't have this problem, or it's not as bad. It depends on how the game was programmed.

[Chief Blur Buster]

We've noticed that GPUs can have a very minor lag-increase effect when GPUs hit 99%-100% utilization in some games.

It is a problem that also afflicts Twitch streamers -- because the stream compressor have no GPU horsepower left to compress the Twitch streams. This is currently being discussed in #streaming-tech-talk in sprEEEEzy's channel on Discord. (I, as Chief Blur Buster, moderate a different channel, #monitor-tech-talk on that Discord server).

It's heavily influenced by the game programming, as it is only a problem with some games.

The problem is a little bit less if you use exclusive borderless windowed mode, rather than windowed -- because the 99-100% GPU utilization can slow down the Windows compositor a bit (little GPU left for Windows desktop compositing).