Input lag when Vsync is on

[jermin]

After I turned on Vsync and triple buffer in the my Nvidia Control Panel, I was experiencing mouse lag both in the main menu and in the game. The cursor moved around 1 second behind the mouse movement. Not only the mouse was lagged, but joystick input (axes, buttons) and TrackIR Input was also delayed for about 1 second.

All these have resulted in very poor aircraft performance in the game. Actually I didn't discover it until several days ago. I even started to think that other online players were using cheats, because I was unable to keep up with an enemy in the same plane in a level turn. He would usually get into firing position in less than 2 full-circle turns.

Actually I have been flying like this for about 2 years. You can imagine how frustrated I had been. I always felt that the joystick in the cockpit moveed behind the real joystick I was using. But I tried to persuade myself that it was merely illusion.

Until several days ago, when I turned off the triple buffer (I can still run IL2 with FPS fixed at 75 with triple buffer off), I was like playing a brand new game. All planes responded MUCH faster (bank, pitch, yaw, throttle). I was able do tight turns very quickly. Then I tweaked my video card further by setting Maximum pre-rendered frames to 0. The result was even better.

I've been playing with this setting for a few days. But I still can feel the mouse lag (around 0.2 second) in the main menu and the game. And I'm afraid other input devices are still suffering from the delay. I tried firing MK108 shot by shot. And I could feel the delay between the trigger action and cannon firing. As you know, a 0.2 second delay of firing during a high-speed deflection shot will result in much longer aiming lead, especially for cannons with low muzzle velocity.

However, there wasn't any input lag when I turned vsync off. But horrible screen tearing makes the game unplayable.

Is there any way to eliminate the input lag while enabling vsync?

[ocococ]

No you can't. Buffers add latency. No way around that.

Simple Vsync is always Double Buffered, which always adds some latency.

Triple Buffered Vsync adds even more latency, but increases and smooths out FPS.



The only thing you can do is get a true 120Hz monitor (eg. good old CRT or some of the new 120Hz gaming LCDs) and run with vsync off. That way you won't have tearing/latency.

[MadBlaster]

i think the settings "max pre rendered frames" only works when you run the game in directX mode. if your running open g/l, it isn't doing anything.

[{HVY-E}Jinxx]

Originally Posted by jermin

After I turned on Vsync and triple buffer in the my Nvidia Control Panel, I was experiencing mouse lag both in the main menu and in the game. The cursor moved around 1 second behind the mouse movement. Not only the mouse was lagged, but joystick input (axes, buttons) and TrackIR Input was also delayed for about 1 second.

All these have resulted in very poor aircraft performance in the game. Actually I didn't discover it until several days ago. I even started to think that other online players were using cheats, because I was unable to keep up with an enemy in the same plane in a level turn. He would usually get into firing position in less than 2 full-circle turns.

Actually I have been flying like this for about 2 years. You can imagine how frustrated I had been. I always felt that the joystick in the cockpit moveed behind the real joystick I was using. But I tried to persuade myself that it was merely illusion.

Until several days ago, when I turned off the triple buffer (I can still run IL2 with FPS fixed at 75 with triple buffer off), I was like playing a brand new game. All planes responded MUCH faster (bank, pitch, yaw, throttle). I was able do tight turns very quickly. Then I tweaked my video card further by setting Maximum pre-rendered frames to 0. The result was even better.

I've been playing with this setting for a few days. But I still can feel the mouse lag (around 0.2 second) in the main menu and the game. And I'm afraid other input devices are still suffering from the delay. I tried firing MK108 shot by shot. And I could feel the delay between the trigger action and cannon firing. As you know, a 0.2 second delay of firing during a high-speed deflection shot will result in much longer aiming lead, especially for cannons with low muzzle velocity.

However, there wasn't any input lag when I turned vsync off. But horrible screen tearing makes the game unplayable.

Is there any way to eliminate the input lag while enabling vsync?

Enabling Vsync DOES NOT CAUSE LAG!!!!
Vsync merely matches the vertical refresh rate of your GPU to your monitor.
ie. If your monitor is 60Hz, the maximum number of frames your GPU will put out will be limited to no more than 60fps +/- 3-5fps.
With Vsync turned off, your card will pump out as fast as it can but if it exceeds the refresh rate of the monitor, you will get vertical tearing.

The problems you're experiencing are very common when your drivers are out of date.

Check your video card drivers and especially the Mother Board drivers/BIOS.
Most often it's the MB drivers that are causing the problem. Specifically the PCI Bus driver.

S!

[von Pilsner]

Originally Posted by {HVY-E}Jinxx

Enabling Vsync DOES NOT CAUSE LAG!!!!

Triplebuffer can cause input lag.

From: http://www.tweakguides.com/Graphics_10.html

[triplebuffering] can introduce control lag. This manifests itself as a noticeable lag between when you issue a command to your PC and the effects of it being shown on screen. This may be primarily due to the nature of VSync itself and/or some systems being low on Video RAM due to the extra memory overhead of Triple Buffering.

However it appears that most recent graphics cards and most new games will not experience major problems by enabling Triple Buffering. Given the fact that it can help to both remove tearing while also preventing the significant FPS drop encountered when VSync is enabled, it is at least worth trying for yourself to see the results on your system.

[MaxGunz]

The lag should be no more than 2 frames, not 1 second.

I was having slow-down problems that I took to be system problems until my video card died. The fan was failing and the card would slow down as it overheated. The process took over 2 months. Input was like the mouse was drunk, FPS would go slide show, and then it would be good for a while. That is one example of what hardware problem can do. Wish I had known what the real problem was instead of thinking something else.