My system gets very good frame rate on "high" settings. But there is still noticeable mouse lag in menus--which is very annoying. Is there a fix for this?

I'm on ...
Windows 7 x64
NVIDIA GeForce GTX 460 video card

Disabling V-sync might help you a little, but the underlying issue is that the mouse is software emulated, and as far as we know, there's no hardware mouse option.

So, no. Unless/until they add hardware mouse support, you're not likely to see your mouse situation improve much (if at all).

You could try turning down some settings to reduce the load on your CPU, to see if that helps, since any lag you're seeing is likely due to the load placed there.

but why does the mouse need to be emulated? why can't they do it in a way that is lag free?

open Documents\Witcher 2\Config\User.ini
Go to [MouseInput] section and set
MouseSmoothness=0
Smoothness=0
then
turn off off uber-sampling AND V-sync

That shold take care of your problems but if your not happy with the results. Then use D3DOverrider to force Vsync on and Triple buffering.

Add/change these values in user.ini under My docs/witcher 2/config:

[MouseInput]
SensitivityX=0.5
SensitivityY=0.5
Smoothness=0
MouseSmoothness=0

Should help.

I set both Smoothness values to 0 as you recommended - didn't do anything.

I find the laggy mouse EXTREMELY irritating. It makes navigating in menus, conversations, selecting prices/amounts etc... VERY slow.

This happens in way too many games. Frankly, I am always pleasantly surprised when the moue movement is as smooth as on the Windows desktop.

So this is an issue of software emulation vs hardware implementation? Nothing we can do?
I must admit, I find it startling that such a basic an essential functionality should have these issues.

It was fixed for me by setting smoothness to 0.

Yes, that's what alwys puzzles me with this issue. Because you would think that the menus are less challenging - in terms of graphics performance and compuataion - than the actual in-world gameplay.

A very simple way; get a new mouse

Are you being sarcastic or are you serious?
You really think it could be the mouse itself? That among various pc mice some would have lag in a game and some not?

Now why would that possibly be the case?

I m just saying it could be that way. you said you have experience this situation in many other games which have totally different engines and configurations. So what else could the problem be?
btw If the mouse itseld has a install cd try to intall the driver again.

don't blame this on mouse hardware or drivers. this is a game performance issue. devs please fix it!

I tried the above settings and it didnt help my mouse lag.
The following settings made it SNAPPY! However, I am not sure which setting solved it, so I provided my user.ini in full.
Good luck.

----cut----
[Engine]
CustomRenderingSettings=0
PerformancePlatform=0

[Input]
KeyboardLayout=QWERTY

[MouseInput]
SensitivityX=0.5
SensitivityY=0.5
Smoothness=1

[Rendering]
AllowAntialias=1
AllowBloom=1
AllowBlur=1
AllowCutsceneDOF=0
AllowDOF=1
AllowDecals=1.0
AllowMotionBlur=0
AllowRain=1
AllowSSAO=1
AllowScatterDOF=0
AllowShafts=1
AllowSharpen=1
AllowVignette=1
AtlasTextureDownscale=0
DanglesLimiter=0
DetailTextureDownscale=0
Fullscreen=1
MaxAtlasTextureSize=2048
MaxCubeShadowCount=1
MaxCubeShadowSize=256
MaxSpotShadowCount=3
MaxSpotShadowSize=512
MaxTextureSize=2048
MeshDistanceScale=0.5
ShadowQuality=0
ShadowedLights=0
TextureDownscale=0
TextureMemoryBudget=400
UberSampling=0
VSync=0

Hey guys, I just want to provide an update for mouse lag with V-sync on and those with ATI cards. Using the free program Radeon Pro I've been able to get very minimal mouse lag by forcing V-sync on and tripple buffering. For those of you that cannot stand screen tearing (me), this is a pretty solid work around, and defiantly minimizes the horrible mouse lag issue.

Make sure to have V-sync turned off in The Witcher 2's graphic options pannel from the launcher, as I find that using RadeonPro to force V-sync; I get better performance than using the in game V-sync.

My Rig:

Windows 7 X64
AMD Pheanom II X4 965 Black Edition
2x4 GB G.Skill Ripjaw RAM
AMD Radeon 6850 1GB