• Competitor rules

    Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.

SLi - Vsync - Input lag

Toadus

Toadus

Toadus

Associate
Joined
3 Apr 2009
Posts
151
Hey :)

I've noticed when playing COD4 or COD5 I get quite noticeable mouse / input lag when Vsync is enabled now that I'm SLi'ing 2 GTX 280's. Previously, Vsync didn't cause any real noticeable input lag, so now that I've enabled SLi, what gives? :confused:

Obviously turning off Vsync means no lag at all, but things don't look half as good. :(
 
I tried setting that option to 1, but it didn't make any difference. The fact that in only effects the game when Vsync is enabled is surely the key here?
 
RaiderX said:
vsync has always caused input lag for me , you might not have noticed it with single card as the framerate without vsync wasnt high enough to cause much of a delay, with sli as the framerate is higher, its waiting longer to render the next frame which is causing the lag, e.g without sli you might be getting 70 fps which is only skipping 1 in 6 frames to make it 60, with sli in ideal conditions youll be getting 140fps which would be skipping just over 1 frame for every 1 displayed and thats whats causing the lag
Click to expand...

I wasn't aware that was how Vsync worked, very interesting!

You may not be aware of this, but you can set the maximum framerate for COD4 within the console system. The command is: /com_maxfps xx Where 'xx' is the framerate. By default, it's set to 85. If your theory is correct, then I could set this command to, say, 70, then enable Vsync, and the input lag should be less. I'll give this a whirl, but I've got a feeling I may have tried this already as I was playing about with it yesterday. By the way, with this max FPS setting on no limit, I noticed there were some areas were I was getting over 350fps, LOL. :eek:
 
Actually, I've answered my own question here...

By default, the max FPS is 85, as per the console command, so when I've been getting the input lag with Vsync enabled, the game would not be allowing more than 85 FPS anyway. So if I manually restrict it to 70 FPS, it's not going to make a blind bit of difference. Hmmm, the mystery continues. I'm guessing Vsync and SLi may have a slight compatibility issue.

GT-Junkie - Are you POSITIVE you don't get ANY input / mouse lag with Vsync enabled? Try turning Vsync off, and see if the cursor movement feels any different?
 
Last edited:
gt_junkie said:
Will double check but i've never had any issues - always felt pretty sharp to me.

Framerates are:

Min: 78
Avg: 120
Max: 245

gt
Click to expand...

Thanks for looking into this.

I found the most obvious way to notice the input lag is: Set up a multiplayer game of your own, in the menu where you get to choose your character, i.e, just before the match starts, move the mouse around, and it feels horrid! All sluggish like it's too slow.
 
Seriously? I couldn't tell the difference from 70fps to 300fps. It all looked shocking... With Vsync enabled, it looks lovely and fresh and smooth, just laggy! :(
 
Ooo, never heard of those COD commands. Can you explain more? :)

Tripple buffering is meant to increase performance when Vsync is enabled, but it's is also meant to cause lag. Also, tripple buffering is not supported in Direct3D games yet, only OpenGL. You can force tripple buffering with certain app tools, but it's actually meant to make lag worse, so I haven't bothered... :)
 
Overslop said:
I was getting very bad input lag with my 4870x2. But after playing about with various settings it turned out to be caused by Vista mouse acceleration! :o

Turned it off and then it worked perfectly. :)
Click to expand...

I only get it with Vsync on, so it can't be mouse settings... :)
 
Rroff said:
Hmm just fired up COD4 and there doesn't seem to be an r_finish command unlike earlier engines :( dunno if theres an equivalent with a different name.

260GTX SLI and a Quad core is just ridiculous in this game - at 2048x I don't think I saw it drop below 250fps.
Click to expand...

Oh bugger...
 
You must log in or register to reply here.
Back
Top Bottom