CS2 Input Lag Explained - The Monolithic 64 Hz Client Simulation Tick Stalls the Render Thread

[cuaderno]

This is on pracc DM server, fps_max 360, 9800x3d, 7900XTX

Thanks for the feedback!

I have some questions:

• Is HAGS on? If not - PresentMon uses legacy kernel scheduler which is not accurate.
• Is Antilag2 on? You might have prerendered frames in the queue which cause input lag but smooth out the graph.
• Are you on vulkan or dx11?

Hey,

1. Hags OFF
2. Antilag2 ON
3. dx11


Tested again on pracc DM with Hags ON (fps_max 360), no difference


Also tested on the awful Valve DM (fps_max 360, Hags ON), which detected the spikes


And empty offline server, spiked again



The feeling of playing on 3rd DM server is noticeably better despite same fps cap value, which matches the findings. Next I can test on official Valve Premier, which never felt as bad as Valve DM server.

[vnb]

This is on pracc DM server, fps_max 360, 9800x3d, 7900XTX

Thanks for the feedback!

I have some questions:

• Is HAGS on? If not - PresentMon uses legacy kernel scheduler which is not accurate.
• Is Antilag2 on? You might have prerendered frames in the queue which cause input lag but smooth out the graph.
• Are you on vulkan or dx11?

Hey,

1. Hags OFF
2. Antilag2 ON
3. dx11


Tested again on pracc DM with Hags ON (fps_max 360), no difference


Also tested on the awful Valve DM (fps_max 360, Hags ON), which detected the spikes


And empty offline server, spiked again



The feeling of playing on 3rd DM server is noticeably better despite same fps cap value, which matches the findings. Next I can test on official Valve Premier, which never felt as bad as Valve DM server.

very interesting. So this confirm what i've been saying for months here...

Community servers have different networks settings (packets pacing, < MTU, margins, and others) which also affects the gameplay and how it feels overall.

Also your results are much cleaner than OP because the 7900 XTX has a hardware scheduler while Nvidia GPUs have heavy reliance on software drivers scheduler, which naturally create a CPU overhead and less clean results.

[Babluga]

what do you think about this? CS2 DM server 60 sec

360 FPS cap


Uncap

[cuaderno]

Ok, so I did random testing of different variables to see if anything stood out.

Using AMD Chill and RTSS async made the spikes disappear in the capture tool, but this is not fixing the root issue.

Here are other variables that I tried using and made no difference (ie, the spikes were present)
Launch options: noantilag, insecure
Servers: gamersclub dm and warmupservers dm (they had noticeably less spikes than Valve dm servers, but more spikes than pracc dm servers)
VSYNC On or Off, Freesync On or Off
High ping and low ping connections
Vulkan or dx11
Valve Premiere and Rush servers

[soul4kills]

Looks like it's a side affect of gsync+vsync enabled.

edit: added 3 separate readings playing a cs server. focused on the peak to peak distribution reading as that's what matters. I'm not getting that 64hz peak to peak interval that's being discussed.

[cuaderno]

Looks like it's a side affect of gsync+vsync enabled.

What refresh rate and what cap value did you use?

The spikes show up a lot less on the capture when I cap low, such as fps_max 324 at a 360hz display, even with sync off.

The odd behavior is that despite using fps_max 324, the in-game cap never goes higher than 315 fps. If I used at higher number, like fps_max 360, it would stay steady at 360 fps but the spikes appeared.