Dual 5770's low fps

[zookeeper525]

I'm running a 2500k underclocked at 3.3 (turbo is off, so it stays at 3.3 as for why i did it is a long story that involves the power in my house) anyway, when running bc2, i'm getting about the same fps as running one. It jumps all over and goes up to 120fps, but says around 70-80fps, but with one 5770 i get 60fps on avg, so i don't really understand why my fps keep dropping so much, it's the same with the witcher 2. I play on high and only get about 60-80fps with crossfire.

Am i doing something wrong, or is that normal? I thought that adding another 5770 would double my fps.

 

[HostileDonut]

It may not be using all of the GPU power it has to offer. What res and settings?

 

[bystander]

Crossfire and SLI rarely produce double the frames of a single card. I think on average, you would expect about 60-70% improvement. However, not all games are going to improve that much.

Sometimes adding a 2nd card will take your graphical performance to a point that your CPU cannot keep up, so you won't get the full potential from your GPU's. This is going to happen more often for you, as a result of being underclocked on your CPU.

One more thing to realize. If your monitor is a 60hz monitor (most are), your monitor can only display a maximum of 60 FPS. When you create more, they are wasted, and often causes an effect called screen tearing. This is not a good thing, and it's usually advisable to turn on v-sync to cap the FPS at 60.

If you are getting 120 FPS, half of those frames are not being displayed and the crossfired setup is kind of wasted. However, when you play more demanding games, like Metro 2033, that extra power is going to be needed to get you to 60 FPS at max settings (or less).

 

[zookeeper525]

res is 720p (ik its shitty, but didn't have enough money to upgrade my monitor yet)
and the settings are stock, i just plugged the second card in and enabled crossfire.


@bystander I never even knew the 60hz meant that the max fps was 60, i'm gonna start putting vsync on, still it didn't really seem normal and didn't really seem like a 60-70% boost over one card more like 10%

 

[HostileDonut]

Yeah, I bet you are not really utilizing the other GPU. Yes, you are probably capped at 60 FPS too.

 

[zookeeper525]

Well, does that mean i have to change something or does it mean since my other card already maxes out the 60fps that the other card doesn't have to try?

 

[HostileDonut]

Well, does that mean i have to change something or does it mean since my other card already maxes out the 60fps that the other card doesn't have to try?

Yes, the second card is basically a backup making sure you don't dip in FPS. Most monitors are 60-75hz, so if you put it at 75hz, you could cap it at 75 instead of 60.

 

[zookeeper525]

If i put vsync on from now on would it make it easier for both cards to max out the 60fps or harder?

 

[bystander]

I like to put v-sync on so the cards don't work as hard if they go beyond my refresh rate. It also reduces/removes tearing.

 

[christop]

I added another 5850 to my rigg and did not see a huge increase. I am gaming at 1900x1200 on a 25.6 inch lcd. I also noticed crossfire is more buggy than sli.

 

[HostileDonut]

If i put vsync on from now on would it make it easier for both cards to max out the 60fps or harder?

Okay, when your frame rate goes beyond what your monitor can run, it can produce tearing. Tearing is when your image looks like it has been torn. When you put on v-sync, it will cap your FPS at your refresh rate. With all of that GPU horsepower, it will maintane your FPS at a solid 60FPS. It doesn't make it harder or easier to get 60 FPS, those are detail, AA, AF, etc settings.