Source engine question

[Spork829]

I have never been able to use Vsync in games running Source engine without noticeable mouse input lag. Haven't tried it with most Source games, but it happens with both TF2 and CS:GO. Is this a common problem with Source and is there a fix?

[Rob.S]

12 minutes ago, Spork829 said:

I have never been able to use Vsync in games running Source engine without noticeable mouse input lag. Haven't tried it with most Source games, but it happens with both TF2 and CS:GO. Is this a common problem with Source and is there a fix?

not a problem with the source engine, but a general problem with all VSync as far as I know. The more fps though, the less tearing.

[GreezyJeezy]

Vsync seems pretty useless TBH it fucks with a lot of games 

[Spork829]

45 minutes ago, Rob.S said:

not a problem with the source engine, but a general problem with all VSync as far as I know. The more fps though, the less tearing.

So is there no fix? It only happens to me in those two games that I notice.

[Shahnewaz]

1 hour ago, Spork829 said:

I have never been able to use Vsync in games running Source engine without noticeable mouse input lag. Haven't tried it with most Source games, but it happens with both TF2 and CS:GO. Is this a common problem with Source and is there a fix?

This is not a Source Engine problem, this is due to how V-Sync works. V-Sync makes your GPU wait before your screen has finished refreshing, so your inputs during the wait is not shown on screen.

This happens with every screen refresh (if your GPU is rendering more frames than the monitor can refresh at any given time), and hence the constant input lag. The problem should be visible with every game, but since Source games run so fast, the input lag is most noticeable on Source games.

 

1) The simplest solution is to just turn V-Sync off. You will eliminate input lag, but introduce tearing.

 

2) The competitive-play solution is to turn off V-Sync and set your fps_max setting in console to as high as possible. This reduces input lag to a minimum, but tearing remains.

 

3) A balanced solution is to turn off V-Sync, and set your fps_max setting to your monitors refresh rate. This will reduce both input lag and tearing. This will not, however, reduce input lag to a minimum.

 

In the first three solutions, you will have constant display lag regardless of your game settings. Display lag can be only reduced by faster refresh rate monitors, or overclocking your monitor.

 

4) The expensive solution is to buy a high refresh rate monitor, leave V-Sync off, and adjust your fps_max setting to match your high refresh rate monitor. Tearing, input lag and display lag will be reduced. Again, input lag will not be reduced to a minimum.

 

5) Finally, the best solution for competitive play is to do solution No. 2, with a high refresh rate monitor. This will reduce display lag, reduce input lag to a minimum, but bring back tearing.

 

Minimum input lag is a critical point for competitive gaming. So is display lag too, but displays can only go so much faster through time. The fastest I've heard yet are 240Hz monitors.

 

Q) But...but if I have minimum input lag with considerable display lag, how does that work?

A) Good question. See, games doesn't require your monitor to refresh first, and then poll your mouse movement. These two processes are asynchronous. So even if you have noticeable display lag, you can still fire your weapon or do movement while your display is in the middle of a refresh. You'll just see it fire or happen at the next refresh, but you will kill your enemy or take cover, regardless of your display refreshing on time or not. The point is to reduce as much lag as possible from as many sources as possible.

 

Q) Why does only lowering my fps_max increase input lag?

A) This is a tricky question. There is debate and confusion on whether the game engine runs slower with lower FPS or not, and people seem to report anywhere between no input lag, to noticeable input lag. So to stay safe, just run your FPS as high as possible.

 

Q) What about tearing?

A) A little bit of tearing is not a big deal when you're gaming, since you trade it for vastly reduced input lag. It's a worthwhile trade-off. If you have too much tearing, then you can bring down the fps using console, but you bring back some input lag.

 

So, is unlimited fps is the only way to completely eliminate input lag?

Yes.

 

[Spork829]

4 minutes ago, Shahnewaz said:

This is not a Source Engine problem, this is due to how V-Sync works. V-Sync makes your GPU wait before your screen has finished refreshing, so your inputs during the wait is not shown on screen.

This happens with every screen refresh (if your GPU is rendering more frames than the monitor can refresh at any given time), and hence the constant input lag. The problem should be visible with every game, but since Source games run so fast, the input lag is most noticeable on Source games.

 

1) The simplest solution is to just turn V-Sync off. You will eliminate input lag, but introduce tearing.

 

2) The competitive-play solution is to turn off V-Sync and set your fps_max setting in console to as high as possible. This reduces input lag to a minimum, but tearing remains.

 

3) A balanced solution is to turn off V-Sync, and set your fps_max setting to your monitors refresh rate. This will reduce both input lag and tearing. This will not, however, reduce input lag to a minimum.

 

In the first three solutions, you will have constant display lag regardless of your game settings. Display lag can be only reduced by faster refresh rate monitors, or overclocking your monitor.

 

4) The expensive solution is to buy a high refresh rate monitor, leave V-Sync off, and adjust your fps_max setting to match your high refresh rate monitor. Tearing, input lag and display lag will be reduced. Again, input lag will not be reduced to a minimum.

 

5) Finally, the best solution for competitive play is to do solution No. 2, with a high refresh rate monitor. This will reduce display lag, reduce input lag to a minimum, but bring back tearing.

 

Minimum input lag is a critical point for competitive gaming. So is display lag too, but displays can only go so much faster through time. The fastest I've heard yet are 240Hz monitors.

 

Q) But...but if I have minimum input lag with considerable display lag, how does that work?

A) Good question. See, games doesn't require your monitor to refresh first, and then poll your mouse movement. These two processes are asynchronous. So even if you have noticeable display lag, you can still fire your weapon or do movement while your display is in the middle of a refresh. You'll just see it fire or happen at the next refresh, but you will kill your enemy or take cover, regardless of your display refreshing on time or not. The point is to reduce as much lag as possible from as many sources as possible.

 

Q) What about tearing?

A) A little bit of tearing is not a big deal when you're gaming, since you trade it for vastly reduced input lag. It's a worthwhile trade-off. If you have too much tearing, then you can bring down the fps using console, but you bring back some input lag.

 

So, is unlimited fps is the only way to completely eliminate input lag?

Yes.

Well that was informative XD. Thanks!

[Shahnewaz]

4 minutes ago, Spork829 said:

Well that was informative XD. Thanks!

No problem! I added 1 more Q/A, if you have further confusions.

Quote

Q) Why does only lowering my fps_max increase input lag?

A) This is a tricky question. There is debate and confusion on whether the game engine runs slower with lower FPS or not, and people seem to report anywhere between no input lag, to noticeable input lag. So to stay safe, just run your FPS as high as possible.