Does undervolting GPU detrimentally effect input lag and latency?

[benjji1]

Hi,
I've been testing an undervolt for my 3090 (0.975v 1890, 1920 mhz when boosted) on some games and although there is no stutter or temperature issues, mouse movement feels different in comparison to base with no undervolting. is actually occurring? or is it placebo? the mouse feels slightly faster when my GPU isnt undervolted, GPU is not maxed out usage wise either. Could it just be the way my undervolt is configured? as i've set a base 60mhz overclock then adjusted the voltage down ( following this guide https://github.com/LunarPSD/NvidiaOverc ... dervolting) i've also added a screenshot of my undervolt curve.
Thought i'd just ask as i couldn't really tell for sure myself and wanted more opinions on the topic.

[Sandy]

Hi,
I've been testing an undervolt for my 3090 (0.975v 1890, 1920 mhz when boosted) on some games and although there is no stutter or temperature issues, mouse movement feels different in comparison to base with no undervolting. is actually occurring? or is it placebo? the mouse feels slightly faster when my GPU isnt undervolted, GPU is not maxed out usage wise either. Could it just be the way my undervolt is configured? as i've set a base 60mhz overclock then adjusted the voltage down ( following this guide https://github.com/LunarPSD/NvidiaOverc ... dervolting) i've also added a screenshot of my undervolt curve.
Thought i'd just ask as i couldn't really tell for sure myself and wanted more opinions on the topic.

You need to turn it on and off repeatedly and observe it for a few days. Based on my experience, it may return to its original state.

[ChristophSmaul1337]

Some GPUs, especially from NVIDIA, have something called "clock stretching". It's a hardware level feature to avoid crashing. When the GPU "notices" that it'll be unstable at its current frequency/voltage setting it can skip instructions, essentially doing less effective work. The tricky part is that this doesn't reduce the core clock, you'll still see a constant core clock while observing diminished scores on benchmarks. You can't directly test for clock stretching (unless you know how to "ask" the GPUs voltage controller via I2C), however you can get a good idea if it's happening with benchmarking software. Reset your GPU to stock, run a 3Dmark TimeSpy, note down the "Graphics Score" result and then do the same thing while undervolted. Make sure to record the core clock to make sure possible diminished performance wasn't caused by a lower core clock in the first place. If you see lower scores outside the margin of error, your GPU likely has clock stretching and therefore your undervolt lowers performance without you even noticing. Note that not every GPU has this, my 2080Ti for example doesn't do this and outright crashes when applying a too low voltage.

Also just a quick heads up, this also happens on newer AMD Ryzen CPUs (2xxx and newer) and - i think - on recent Intel ARC GPUs, too.
EDIT: Intel 12th gen CPUs do this, too. The newer generation CPU's likely will also do it, although i don't have information about them.

Cheers

[6spd_legend]

Really interesting post- I've been battling a variance in input latency for years with my build (I only play halo infinite online)- and for a long time I too was on an undervolted 3090. I recently went back to stock configuration (along with a bunch of other tweaks)- but overall my system feels much better and my aim is noticeably improved...