Just got second GTX 560 Ti - SLI Setup Q's

[Holymartyr]

From the thread title I just go my second GTX 560 Ti, and was wondering what I have to do, if anything beyond checking the "Maximze SLI Performance" box in the NVidia control panel.

 

I've heard about SLI AA and that Skyrim has issues with SLI, not sure if these were resolved in the latest WHQL drivers or not (301.42 I think).

 

Any/all input welcome! Thanks! =)

[torminater]

Enable stereoscopic 3D and disable in-game effects for curing the SLI Water Bug.

Also be sure to have the newest WHQL nvidia drivers installed.

It might be that you have less VRAM stutter with only ONE graphic card active. But it will decrease your framerate to disable SLI. It's Loss-Loss situation...

[Holymartyr]

Yeah, to my disappointment, I've gotten either no, or very little fps increase. 2 560 TI's cannot handle AO with x4 MSAA and x4 SGAA...

 

Wish I had sold my first Ti now and gotten a new GTX 670...=( Oh well..., live and learn.

[frihyland]

That's why I wrote the hardware guide :(

[Holymartyr]

Update:

 

I found out that when you click "enable stereoscopic 3d" and stop it from loading (the water bug fix for SLI) - it disables SLI entirely. I'm not sure what my game was doing, because both GPU's were being used, but i didn't get any increase in FPS and in fact got a random black screen from all my games if I played them too often - forcing me to do a hard reboot.

 

I've since disabled stereoscopic 3d, and now Skyrim is running 60 FPS+ with AO, x4AA and x4SGAA.

 

To fix the annoying water bug, I set bUseWaterDisplacements=0 (used to be 1) - this disables the water ripples around you when you enter the water and in return stops the bug from occuring.

 

I'd say its a very very, subtle and minor loss IMO compared to all the FPS gained WHILE using AO and better AA =D

[torminater]

Yep, came back here, because I remembered you said something like that!

There is also another bug with sli and water, if you didn't notice:

Reflections on water shake/jump rapidly when moving from side to side.

Only known fixes:

a) disable sli

b) enable 3D

c) turn off water reflections for sky, objects, land and trees in skyrim game launcher (or skyrim.ini if you prefer it this way, note that if you only disable bUseWaterReflections you will still get reflections on water when playing, but none on the map plus the reflections look kinda weird.)

 

There is a problem with c) though: the game looks shitty. Of course there is a tradeoff possible: the reflections of trees are the most noticeable nuisance. You can keep the other reflections on. You'll notice the jumping only when paying lots of attention to it.

[torminater]

OK, I've got some news for you: The SLI "Fix" no longer works. At least not with the whql 310 drivers from Nvidia.

So, the only possible fix is to disable SLI completely. Which sucks... Badly.

[TechAngel85]

What fix are you referring to? SLI and Crossfire have notoriously always been unreliable in Skyrim. Remember, Skyrim was built on technology to run in Windows XP when SLI and Crossfire weren't that popular.

[torminater]

Enabling 3D and disabling it ingame won't work anymore to get rid of the SLI Bugs.

[torminater]

OK, I'm thinking about getting myself a new graphics card. Since I'm not all to happy with the support of SLI technology, I'ld like to stick to a single graphics card. Now I know one of the newest graphics cards from NVidia has 2 GPU's, does that mean they need to be in SLI to get it's full potential? Cuz that would suck.

[TechAngel85]

OK I'm thinking about getting myself a new graphics card. Since I'm not all to happy with the support of SLI technology, I'ld like to stick to a single graphics card. Now I know one of the newest graphics cards from NVidia has 2 GPU's, does that mean they need to be in SLI to get it's full potential? Cuz that would suck.

I don't think so. It's one a single card so think of it as a dual-core GPU.

[Neovalen]

OK I'm thinking about getting myself a new graphics card. Since I'm not all to happy with the support of SLI technology, I'ld like to stick to a single graphics card. Now I know one of the newest graphics cards from NVidia has 2 GPU's, does that mean they need to be in SLI to get it's full potential? Cuz that would suck.

If your talking about the GTX690 it acts as if it is in SLI. Same for the ATI equivalent. SLI/Crossfire is the wave of the future... sad that Skyrim is based on such an old engine.

[torminater]

So does the GTX 690 need SLI enabled or not???

[JudgmentJay]

If you want to use both GPUs, yes, it's basically SLI. You can un-SLI them and use the second GPU for PhysX, but that seems pretty dumb.

 

Also keep in mind that the actual amount of VRAM is typically half of what they advertise on dual GPU cards. The 690 only has 2GB of VRAM.

[TechAngel85]

So does the GTX 690 need SLI enabled or not???

I went out of my way to find an answer to this question and finally ended up contacting NVIDIA support. Here what they said:

Karthik: Hi, my name is Karthik. How may I help you?

Jeremy: Hi, I have a question. I'm considering purchasing a GTX 690 and can not find a straight answer.

Jeremy: Since having two GPUs does the card run in SLI mode in the drivers or does it act as a single card?

Karthik: I will answer this query Jeremy,

Karthik: This card can be set in SLI since it has 2 GPUs. It can be set from the NVIDIA control panel---set PhysX configuration.

Jeremy: So, if I have an older game that doesn't support SLI, would it mean that the video card would only use one of the two GPUs; not both?

Karthik: Yes, that is right. If the game doesn't have the SLI profile, it will use only one GPU or you can disable the multi-GPU mode to play the game.

Jeremy: Okay, thank you very much. You've answered my question.

Karthik: you are welcome & do stay in touch with us, if you have further queries and need assistance, I would be happy to help you.

So, basically if you can't get SLI to work then the card is only going to use one of the GPUs.

 

Also, here is a good review. Two videos on the page. The second one loads after the first is done. Newegg

NVIDIA also has some good benchmarks; one of them is Skyrim. (Performance section)

[Neovalen]

The problem with Skyrim in SLI is not performance but rather minor glitches like no HDR/flickering water. Disabling SLI resolves these but I find I generally don't notice the problems unless I look for them.