Page 1 of 1

g-sync input lag in emulation and g-sync in general question

Posted: 31 Oct 2018, 17:58
by ChocolateLovin69
i posted in this forum because i wasn't sure where else to ask this. for emulating melee on dolphin which will reduce input lag more? 144hz (in game 60 hz) with gsync+sync or or 144hz (in game 60hz) with no sync. i ask this its not very clear when citing blur busters bonus tidbit on g-sync for emulation
Often overlooked is G-SYNC’s ability to adjust the refresh rate to lower fixed framerates. This can be particularly useful for games hard-locked to 60 FPS, and has potential in emulators to replicate unique signals such as the 60.1Hz of NES games, which would otherwise be impossible to reproduce. And due to the scanout speed increase at 100Hz+ refresh rates, an input lag reduction can be had as well…


is that input lag reduction relative to 60hz monitors because its 144hz or relative to not using v-sync because of the fixed scanout speeds at lower refresh rates? which one is less input lag??
also does this even make a difference for faster melee builds for those in the know? for those who don't know what that is, to describe it simply to the best of my ability, its a mod of melee running at 120fps in order give it faster scanout and reduce input lag. you can read more about it here http://fastermelee.net/archive/

on a bit of a side note i know this has probably been answered a billion times in this forum will i benefit more in competitive games like overwatch and csgo (and possibly melee/faster melee) from the slightly lower input lag of no sync or the reduced tearing and artifacts
to add to that on an even simpler side note that's probably been answered even more is there even a difference between g-sync+v-sync vs no sync in super high refresh rate games? would i be better off saving g-sync for games that aren't very competitive in order to make it smoother at lower refresh rates

i know this post is a mess so thank you to anyone who answers any of my questions

Re: g-sync input lag in emulation and g-sync in general ques

Posted: 31 Oct 2018, 19:32
by RealNC
ChocolateLovin69 wrote:i posted in this forum because i wasn't sure where else to ask this. for emulating melee on dolphin which will reduce input lag more? 144hz (in game 60 hz) with gsync+sync or or 144hz (in game 60hz) with no sync.
Input lag should be the same in both cases. G-Sync will remove tearing and FPS/Hz mismatch judder without adding input lag. It will NOT reduce input lag below what is already the minimal input lag possible (if you run 144Hz vsync OFF, that's the lowest input lag you can possibly have.)
Often overlooked is G-SYNC’s ability to adjust the refresh rate to lower fixed framerates. This can be particularly useful for games hard-locked to 60 FPS, and has potential in emulators to replicate unique signals such as the 60.1Hz of NES games, which would otherwise be impossible to reproduce. And due to the scanout speed increase at 100Hz+ refresh rates, an input lag reduction can be had as well…

is that input lag reduction relative to 60hz monitors because its 144hz or relative to not using v-sync because of the fixed scanout speeds at lower refresh rates? which one is less input lag??
G-sync will have lower input lag than vsync regardless of refresh rate. So the comparison here is with 60Hz regardless of sync method.
also does this even make a difference for faster melee builds for those in the know? for those who don't know what that is, to describe it simply to the best of my ability, its a mod of melee running at 120fps in order give it faster scanout and reduce input lag. you can read more about it here http://fastermelee.net/archive/
I don't think any of this is relevant. G-Sync will not reduce input lag lower than vsync OFF. It will also not increase it. On average, G-Sync has the same latency as vsync OFF. So if you normally run Melee with vsync OFF, then switching to G-Sync will neither increase nor reduce input lag.

If you normally run Dolphin with vsync OFF and use the 120FPS hack, then using g-sync instead will have no impact on latency. The only impact will be visual (tearing and judder will be gone.)
to add to that on an even simpler side note that's probably been answered even more is there even a difference between g-sync+v-sync vs no sync in super high refresh rate games?
Yes. With gsync + vsync ON, when FPS reaches Hz - 2, then you get latency almost as high as normal vsync. If you use gsync + vsync OFF, then gsync is disabled when FPS reaches Hz - 2.

So if you want to make sure gsync is active, cap your FPS to Hz - 2 at least, or Hz - 3 to be on the safe side. All this is explained in detail, with lots of tests in our G-Sync 101 article (14 pages):

https://www.blurbusters.com/gsync/gsync101
would i be better off saving g-sync for games that aren't very competitive in order to make it smoother at lower refresh rates
That's subjective. I play OW and CS:GO with g-sync and an FPS cap of 162FPS (I'm on a 165Hz display.)

Re: g-sync input lag in emulation and g-sync in general ques

Posted: 31 Oct 2018, 20:40
by Chief Blur Buster
NOTE: For emulators

Capping tricks are not necessary for emulators as the emulator 60fps is a defacto in-app cap.

Input lag is naturally low in emulators as long as you've gotten the emulator to run in GSYNC/FreeSync mode.

For fixed-Hz, use the highest Hz multiple. For 240Hz monitors use 60fps at 240Hz. That reduces the scanout latency to ~4ms differential for top screen edge versus bottom screen edge.