Just enabled SLI, now games seem choppy at 40fps

[walmartshopper]

I just installed a 2nd 7800gt and enabled SLI. The framerates are great, but when it starts dropping down to around 40fps, the game starts feeling choppy. So it shows 40fps, but it feels more like 20fps.

I'm using 91.31 drivers. One card is an XFX and one is a BFG. Both come with factory OC and have the exact same pcb layout, so that shouldn't be a problem. Could this maybe happen if the cards have different firmware revisions?

I'll try the 80 series drivers and see if it helps. Any other ideas?

 

[unfalliblekrutch]

Maybe you're getting used to higher FPS and can more easily tell when FPS drops?

Or are you talking about stuttering?

 

[walmartshopper]

It's kinda hard to describe. I know what low fps feels like because I can usually tolerate anything above 20-25fps. But it was almost unplayable even at 40fps. It's not stuttering like from lack of ram cuz i have 2gb. It's more like when I turn around, the movement seems very uneven, as if it were skipping some frames.

But anyway, I just installed 84.21 and the problem is gone. Must have been something with 91.31.

 

[LittleNemoNES]

The problem is Vsync. I had a similar setup last year and it was weird to see high FPS but the game felt choppy anyway. Went ATI -- problem solved...except in FEAR

 

[CP5670]

I noticed exactly the same thing with my SLI setup and eventually switched to a single card mainly because of this issue. This seems to be related to vsync in some way, since it only occurs in games where vsync doesn't work on SLI (which means most of them, unfortunately), but it's something more than the normal tearing you get on a single card.

 

[Elfear]

Originally posted by: CP5670
I noticed exactly the same thing with my SLI setup and eventually switched to a single card mainly because of this issue. This seems to be related to vsync in some way, since it only occurs in games where vsync doesn't work on SLI (which means most of them, unfortunately), but it's something more than the normal tearing you get on a single card.

:thumbsup:

Had exactly the same experience. I got great frames with SLI but I couldn't stand the tearing. Main reason I went with a single card.

 

[akshayt]

why haven't you used identical cards?
Isn't it a better idea to sell both these cards and get a single 512mb radeon 1900xt/1800xt

 

[n7]

I love hearing about all these great "features" we get with SLI (& CF too).

Sad how poorly implemented both dual GPU methods are still...

 

[josh6079]

Had the same problem here. Supposedly Triple Buffering along with Vsync is supposed to fix that, but I couldn't tell you anymore since I no longer have both cards. When I did have both of the I tried to get triple buffering to work on BF2, but, at the time, was unsuccesful. Since then I've discovered how to do it, but now have the single X1900XTX.

I agree, one card is less troublesome than two, but also can be less rewarding in quality and frames. It's just a matter of what is most important to the user.

 

[Matt2]

I do miss the intensely high framerates of SLI, but thats about it.

 

[moonboy403]

what i did with my 7800 gt sli and 7900 gtx sli was using directxtweak or something like that...i don't quite remember

using that along with manually choosing how the game renders in sli mode will allow you to enable triple buffering, hence solving the problem with vsync

 

[walmartshopper]

Thanks for all the suggestions. It's running very well with the 84.21s now. Movement is very smooth, no more issues. Loving the fps.

 

[TheRyuu]

I have SLI (as sig implies) and I've noticed that too sometimes.

The 84.21's and 84.22's were both very good drivers. The only drivers that I found worked better were the Xtreme-G 91.31's (select). They just seem great for my rig. Fast performance, great IQ, smooth framerate, all the good stuff like that.

Sometimes modified drivers help, sometimes they don't. It all depends on the rig. I also use the 91.31's because of the Oblivion performance enhancements that the 82.21's don't have.

Also, the 84.37's were also very good.

 

[Ika]

Originally posted by: akshayt
why haven't you used identical cards?
Isn't it a better idea to sell both these cards and get a single 512mb radeon 1900xt/1800xt

please stop posting.

 

[CP5670]

Originally posted by: Elfear
:thumbsup:

Had exactly the same experience. I got great frames with SLI but I couldn't stand the tearing. Main reason I went with a single card.

I had heard about the vsync problems and was a little wary before I got the cards, but read this on Nvidia's SLI website and thought there were no issues. Rather misleading stuff IMO.

The tearing on a single card actually doesn't bother me much in many games, but the screen seemed to tear in four or five places at the same time with SLI, which created the perception of choppy performance even when the framerate was well over 100.

Originally posted by: moonboy403
what i did with my 7800 gt sli and 7900 gtx sli was using directxtweak or something like that...i don't quite remember

using that along with manually choosing how the game renders in sli mode will allow you to enable triple buffering, hence solving the problem with vsync

I tried a lot of things with that program but many games wouldn't work with vsync at all. Either the tearing was still there or the performance dropped to the level of a single card with vsync on. SLI worked perfectly (with full vsync and TB) in modern OpenGL games and some SFR D3D games, but that was about it. DXTweaker actually works pretty well in most games on a single card, but there are no vsync issues on that.

Originally posted by: walmartshopper
Thanks for all the suggestions. It's running very well with the 84.21s now. Movement is very smooth, no more issues. Loving the fps.

Did the drivers solve your problem? 84.21 (the XG version) was the last driver I used before switching cards and it didn't seem to change anything for me.