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SLI performing WORSE than single card.

sli crossfire gtx 780 graphicscard gpu cpu dual

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#1
AsaHerring

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I did loads of research before I bought another GTX 780, and almost everywhere I read anything from, almost all people said you will see gains going SLI as long as nothing else is holding you back or limiting your system like your CPU. I have a 3570k overclocked to 4.2Ghz. It is my impression that Skyrim is well optimized for SLI.

I will state this. This is my first time going SLI. I do have SLI enabled through the Nvidia control panel and confirmed both GPUs are working with Precision X while in game. I still may have something wrong.

These framerates are from as soon as you enter Whiterun, and I have many mods that affect Whiterun as well as mods that ad NPCs.

(Framerates only changed 1-2fps if am running an ENB or not.)

Framerate without SLI = 20

Framerate with SLI = 18

I was hoping to see at least a small increase at this area, like 10-15 at least, but not a drop.

I have searched online on if there is any setting that you manually have to turn on to enable SLI in game, but everything I read is from 1 or 2 years ago, from like version 1.2 or 1.4 of Skyrim, and the things stated no longer apply, so I assumed it was implemented by default in the later updates.

Also, from monitoring them in game, my GPU usage maxes out around 50% and my CPU maxes out around 60%, not sure why so low even though my fps is so low.

Any advice is appreciated. 



#2

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I have seen what you are describing with SLI before. I am not sure what caused it.

I would guess that the motherboard may be causing it.



#3
AsaHerring

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I have seen what you are describing with SLI before. I am not sure what caused it.

I would guess that the motherboard may be causing it.

Motherboard? Why? Doesn't really seem like a limiting factor at all to me.



#4
AsaHerring

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Updated drivers, 337 to 340. Both are very new drivers, so I didn't think it would change anything since SLI 780 set up was available over a year ago. On 337, in game my GPUs would max out at just over 600MHz, which is very low. After I updated to 340, they would max out at 1097, which is where they're supposed to, but there was no performance difference. I am still so confused why SLI is running slower than one card. 



#5
camaro_69_327

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My SLI 580's do 100 FPS in Skyrim (Monitor refresh rate at 100, Nvidia doing Vsync.)<<That was for testing, i use 1/3 refresh rate giving me 33 FPS. You have to find your bottleneck. Yes a motherboard CAN be the bottle neck , if adding a second card drops the Pci bus to 4x PCI-E instead of say 8 or 16 X ,,,that is cause for serious slow downs.

 

How many drivers have you tried?. The "Skyrim Driver"...290.53, was by far the best driver for SLI till the one i am using now. ALL the 300 series drivers sucked bad, till this one i am currently using>>337.50. Have not tried any drivers since i found this one, as it actually works without crashing the driver. The ROCK steady 290.53 driver wont work for you sadly, as the highest GPU supported is a 500 series GPU.

 

Find the oldest driver that supports your GPU. Try every driver till the latest, the one that tests fastest is what you should use. I will Recommend the 377.50 Driver i am currently using. I play Skyrim for extended times...6-8 hour runs are normal for me. (checked , yes your 780 GPU is covered by this driver).

 

Turn OFF Vsync in Skyrim and ENB (if using) and Only use Nvidia to control Vsync. Turn on Shader cache, Turn OFF Ambient Occlusion, NO AA/AF. 

I use .."Nvidia Recomended SLI" some say AFR 1 (Alternate Frame Rendering 1), is better but not for me..

 

BUT since you have a SLI setup...for grins turn on SLI 64x AA...your FPS will be really low but WOW is it Gorgeous...hahahha.

 

Skyrim plays really well with SLI,,, both my cards run 80 - 90 % load @ 2.8 GB textures.

 

What Motherboard are you using?...



#6
AsaHerring

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My SLI 580's do 100 FPS in Skyrim (Monitor refresh rate at 100, Nvidia doing Vsync.)<<That was for testing, i use 1/3 refresh rate giving me 33 FPS. You have to find your bottleneck. Yes a motherboard CAN be the bottle neck , if adding a second card drops the Pci bus to 4x PCI-E instead of say 8 or 16 X ,,,that is cause for serious slow downs.

 

How many drivers have you tried?. The "Skyrim Driver"...290.53, was by far the best driver for SLI till the one i am using now. ALL the 300 series drivers sucked bad, till this one i am currently using>>337.50. Have not tried any drivers since i found this one, as it actually works without crashing the driver. The ROCK steady 290.53 driver wont work for you sadly, as the highest GPU supported is a 500 series GPU.

 

Find the oldest driver that supports your GPU. Try every driver till the latest, the one that tests fastest is what you should use. I will Recommend the 377.50 Driver i am currently using. I play Skyrim for extended times...6-8 hour runs are normal for me. (checked , yes your 780 GPU is covered by this driver).

 

Turn OFF Vsync in Skyrim and ENB (if using) and Only use Nvidia to control Vsync. Turn on Shader cache, Turn OFF Ambient Occlusion, NO AA/AF. 

I use .."Nvidia Recomended SLI" some say AFR 1 (Alternate Frame Rendering 1), is better but not for me..

 

BUT since you have a SLI setup...for grins turn on SLI 64x AA...your FPS will be really low but WOW is it Gorgeous...hahahha.

 

Skyrim plays really well with SLI,,, both my cards run 80 - 90 % load @ 2.8 GB textures.

 

What Motherboard are you using?...

Thanks for the tips, I will look into those.

I have the AS Rock Z77 Extreme4.

UPDATE:

Tried each of available drivers for the 780, no performance change. My GPU load still stayed right under 50% and my CPU load stayed right under 60%.



#7
AsaHerring

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This is what my vram usage looks like in game. It is maxing out on one card, but is the second card supposed to be doing nothing? 14779079561_cc5ae7f1d4_o.jpg



#8
AsaHerring

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Was doing some more research and I heard someone say that they had the SLI bridge on the pins closes to the video output ports, then switched it to the other ones. Mine was the same, so I switched it to the other ones, loaded up the game, and it looks like this. However, I started having some absolutely INSANE screen flashing. I then switched the SLI bridge back to the pins that it wasn't working on, and it is now working. I have no clue what is going on now... It seems to be working though, but still not performing any better.

14596204267_2f977bfe10_o.jpg



#9

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That motherboard is limited to dual 8x (each card at running at x8 not x16).

This is also the reason I saw it the last time (never confirmed it) 8x each with 2 video cards or 1 card at x16.



#10
AsaHerring

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I was not aware of this. So in the future if I want to run SLI I need to look for a mobo that supports two cards in 16x? Or is it one 16x and one 8x?





Also tagged with one or more of these keywords: sli, crossfire, gtx, 780, graphicscard, gpu, cpu, dual

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