• 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 not smooth below 60 frames per second

mof

mof

mof

Associate
Joined
19 Jul 2011
Posts
290
I've only tried a few games with SLI and I've noticed that when using SLI, in order to make it feel smooth, you need a much higher frame rate than you would need with just one card.

E.g 1. The division with one card running at roughly 30 FPS felt fine to play.
With SLI running in the 40s FPS (also not scaling very well) it felt really stuttery and wasn't really playable. It wasn't until I'd reduced the settings enough to get a constant 60 FPS that it felt smooth to play.

2. The Witcher 3: With SLI getting 50 FPS it doesn't feel good at all. Yet as soon as I get the settings down a bit and it's running at 60 FPS constantly it's playing completely smooth and flawless.

Normally with 1 GPU I can play at 30-45 FPS and not have any problem whereas with multiple GPUs anything below 60 feels crap.

I was playing the Witcher with the frame limit set to 60 (60 Hz monitor) and adaptive v-sync on. I tried turning v-sync completely off but I still got the same result.

Using "smooth v-sync" in the nvidia control panel does help with this but it lowers the frame rate so much that you might as well be on one card.


Is this something that other people find with multi GPU set-ups?
Does it happen with higher refesh rate montiors?
If so then I'm glad I only have a 60Hz one.
 
It has always been my opinion with multi GPU - its best application is when one cards gets around 50fps or so and you use the second to hold a constant 60fps or to get 100+ as much as possible.

If you are needing 2+ GPUs just to get 30fps there will often be less than desirable input latency and frametime variation.

In some games you can improve the situation by reducing maximum pre-rendered frames to 1-2 at a slight performance loss and V-Sync will produce less than desirable results - so adaptive or G-Sync a better option.
 
Depends what gpus you have I suppose? I'm lucky that mine just don't drop so low for me to notice, but I'd be disappointed to have sli and only be getting 40 fps in the Division.
 
cadmunkey said:
Depends what gpus you have I suppose? I'm lucky that mine just don't drop so low for me to notice, but I'd be disappointed to have sli and only be getting 40 fps in the Division.
Click to expand...

Yeh it is disappointing. Although that was @4k with everything turned up. I can change a few settings to get a constant 60. The division seems to have poor scaling despite the high usage on both gpus.

Crysis 3 has great scaling. I haven't tried either of the tomb raiders yet but apparently they scale well too.
 
It can happen but the only time I've had stuttering is with fallout 3. Every other game even at 4K below 60 frames has been fine. Although I have 1440p 144hz now.

Just tried and it doesnt run all that well. Look at benchmarks and you can see the sli optimisation is very poor with this game.
 
Last edited:
Anything below about 50 fps with 1 gpu feels crap unless you have gsync/freesync. Are you sure 1 gpu at 30-45fps is as good as you remember?
 
Drollic said:
Anything below about 50 fps with 1 gpu feels crap unless you have gsync/freesync. Are you sure 1 gpu at 30-45fps is as good as you remember?
Click to expand...

I'll have to try it out. I'm not saying it's perfect but just playable.
The witcher 3 @ 50 felt terrible - more like 15 frames. Didn't look right either it was kind of like tearing but different. It might have been micro stuttering like Meaker said. The frame rate was constantly jumping from 50 to 51 and back again. With smooth v-sync on this didn't happen. It was a constant 30 fps.

I ended up going back to using 1 card for the division.
 
Last edited:
Well I find that for every GPU there's additional input latency which can make things feel horrible :( 60fps with 3 GPUs looks pretty smooth but the delay in input is pretty nasty. I'm not sure how people can play at 60fps with 4 GPUs as it must be even worse! I guess it makes sense when you think about how AFR works...

This of course might not be what you are experiencing and could be just some sort of microstutter as suggested above.
 
mof said:
Yeh it is disappointing. Although that was @4k with everything turned up. I can change a few settings to get a constant 60. The division seems to have poor scaling despite the high usage on both gpus.
Click to expand...
I havent bought the game yet, waiting for a bit of a reduction in price then will check it out.
 
I think it must've been micro stutter. Starting to notice it even when fraps is showing a constant 60 fps (on the Witcher 3).
 
Mauller said:
Max pre rendered frames is actually fixed for SLI, changing the option doesn't do anything.
Click to expand...

Changing the setting ingame in games like BF4 and some others will reduce/eliminate noticeable microstutter at a slight performance penalty.

Via the nVidia control panel is a more complex story (and it has changed since I moved on from my 470 SLI setup so I'm not entirely upto speed on it).
 
I always found SLI stuttery under 60 fps when in fullscreen windowed mode, in pure fullscreen mode it was fine. Especially in witcher 3.
 
Devious said:
I always found SLI stuttery under 60 fps when in fullscreen windowed mode, in pure fullscreen mode it was fine. Especially in witcher 3.
Click to expand...

Thanks. I'll make sure it's fullscreen mode. I thought you couldn't use sli in windowed mode but that must be just crossfire.


Also I think I have a bit of a problem with adaptive v-sync in general. It doesn't get rid of tearing completely or I'm seeing something similar to screen tearing that goes away completely with full v-sync on. I think my monitor (philips bdm4065uc) might be more prone to this kind of thing more than others. Probably not an ideal gaming monitor but I use it for tv/films/wiiu/general pc use aswell.

I'm going to try full v-sync with SLI and see if that helps the performance.
 
Adaptive v-sync will apply regular v-sync when your GPU is outputting 60FPS+ (or whatever your refresh rate is). If the frames dip below the refresh rate, v-sync gets disabled which will result in tearing again.

It's meant for people who want to prioritise frame rate over tearing, the benefit being it doesn't drop to half your refresh rate like normal v-sync.
 
zola25 said:
Adaptive v-sync will apply regular v-sync when your GPU is outputting 60FPS+ (or whatever your refresh rate is). If the frames dip below the refresh rate, v-sync gets disabled which will result in tearing again.

It's meant for people who want to prioritise frame rate over tearing, the benefit being it doesn't drop to half your refresh rate like normal v-sync.
Click to expand...

Yeh that's what I thought it was. Somewhere inbetween v-sync on and off.

I always thought I was getting tearing when the frame rate was below the screens refresh rate but then I heard it only happens when it's above the refresh rate.

So you can still get tearing with adaptive v-sync on when the frame rate is below your screens refresh rate?
 
^ Yes, it's a common misconception that tearing occurs only above the refresh rate. Tearing can actually occur at any time that a frame is not perfectly synced with your monitor's refresh. If a game is running at 45FPS and the monitor outputs at 60Hz it doesnt mean each of those 45 frames will coincide neatly.

V-sync, G-sync and Freesync are the only real solutions to tearing.
 
Indeed, with adaptive v-sync the tearing below refresh rate is deliberate (to stop your frame dropping harshly to next available v sync rate such as going 60fps to 30fps)
 
OP, have you tried locking the frame rate at value which your cards can hold constantly or even don't drop under if it's high enough? You can do it via MSI AB per game (create a profile) and it was a "fix" i used for some games that had bad frame times - back then no one was really talking about this. AMD has a similar option for profiles in the drivers, nVIDIA may have (not sure) as well - in case you dislike Afterburner.
 
You must log in or register to reply here.
Back
Top Bottom