How do SLI driver issues affect games?

[NumeroSieben]

hey everyone,

 

i'm considering a 2 way or 3 way SLI setup. I'm aware 2 way is actually pretty well supported in general but 3 way has a lot more issues, scaling problems etc. So i wanted to ask what these problems are actually like. Can i not launch the game? If i can launch the game, will it use 1 graphics card only with zero SLI support, and 2 cards if it only supports 2 way SLI? 

 

What are the frame problems that 3 way SLI has, i've heard it can cause frame rates being more all over the place, and can also stutter sometimes. Does gsync alleviate this problem?

 

On top of that, is there anything else i should know about 2 way and 3 way SLI?

 

Thanks never had a SLI rig before and i have a lot of money to build a rig that i might be making absolutely ridiculously just because i can soon (3 way GTX 980 sli. Otherwise 2 way is what i'll go with)

 

 

[Sheldon_King]

hey everyone,

 

I am coming from a 2 way Crossfire experience, so your mileage will vary.

 

If the game is coded to use only one GPU, the game will simply not launch the second thread for the second GPU. You would see this as reduced framerates and 0% usage on the second card if you monitor GPU usage in game. I have no experience with 3 way, but I would assume it is the same way, where it just would not launch teh third thread.

 

the rest I can not comment on.

 

Also, follow your own thread next time please.

[FireFox]

I've only ever had 2-way SLI and that was a while ago with a pair of 8800 GT's. Not sure on the performance figures right now until my new board arrives and I can install my second GTX 780 but one thing I would like to add and that is if you want SLI then stick with 2-way.

 

More heat, more power and increased cost of buying another card and running it, also the increase in problems with 3-way.

[AlwaysFSX]

SLI itself doesn't effect games. It's the game's support of the feature that causes it to break.

[NumeroSieben]

I've only ever had 2-way SLI and that was a while ago with a pair of 8800 GT's. Not sure on the performance figures right now until my new board arrives and I can install my second GTX 780 but one thing I would like to add and that is if you want SLI then stick with 2-way.

 

More heat, more power and increased cost of buying another card and running it, also the increase in problems with 3-way.

From what i've seen, it scales well in some games with 3 way, but in many it doesnt. However this doesn't affect me all that much as long as the game actually launches and takes advantage of two threads (rather than 3)

[ChaosGoW]

From what i've seen, it scales well in some games with 3 way, but in many it doesnt. However this doesn't affect me all that much as long as the game actually launches and takes advantage of two threads (rather than 3)

Tomb Raider is leading the pack in scaling for SLI, it's silly how good it is. Most games don't see anywhere near that kind of scaling though, around 40-50% extra frames for 2 way, add another 30% ish for 3 way and that is what to expect in GPU heavy games. Some are more, some are less and some don't work at all with SLI. It's gotten a LOT better now though, it used to be much worse. I don't get stuttering that used to plague SLI supported games, the worst that you can expect now is driver crashes but they're few and far between. If you're playing a game and experiencing these problems you can easily disable SLI for that game in the nVidia drivers and it wont affect the rest of your games.

 

If you really want the extra performance or need it for  a high res screen then go for it, if you're gaming at 1080 on a single screen you don't need it, just get a 970.

[NumeroSieben]

Tomb Raider is leading the pack in scaling for SLI, it's silly how good it is. Most games don't see anywhere near that kind of scaling though, around 40-50% extra frames for 2 way, add another 30% ish for 3 way and that is what to expect in GPU heavy games. Some are more, some are less and some don't work at all with SLI. It's gotten a LOT better now though, it used to be much worse. I don't get stuttering that used to plague SLI supported games, the worst that you can expect now is driver crashes but they're few and far between. If you're playing a game and experiencing these problems you can easily disable SLI for that game in the nVidia drivers and it wont affect the rest of your games.

 

If you really want the extra performance or need it for  a high res screen then go for it, if you're gaming at 1080 on a single screen you don't need it, just get a 970.

I've got a 1440p 144hz screen (asus ROG Swift) and have been considering two highly overclocked aftermarket 980s or three reference 980s to try to push as close to 144fps in as many games as possible which is why i'm interested in Sli since theres no single graphics card that will satisfy my FPS-lust

[ChaosGoW]

I've got a 1440p 144hz screen (asus ROG Swift) and have been considering two highly overclocked aftermarket 980s or three reference 980s to try to push as close to 144fps in as many games as possible which is why i'm interested in Sli since theres no single graphics card that will satisfy my FPS-lust

I have a swift and 2 Strix 980s and there's not a game I'm not happy the frame rates at max settings, it's rare that any game dips below 100 fps and with g-sync it doesn't feel like it's dipping at all.

[NumeroSieben]

I have a swift and 2 Strix 980s and there's not a game I'm not happy the frame rates at max settings, it's rare that any game dips below 100 fps and with g-sync it doesn't feel like it's dipping at all.

 

Yeah honestly from hearing about potential headaches of 3 way SLI, I really want to like it, but i'd only go for it if i had more money to burn. Maybe next build i'll go with a ridiculous 4 way SLI setup just for fun. I really want to see 3 way and 4 way SLI supported like 2 way is haha. 

[Lord Pantaloons]

@Ryan Leech can help here

[ChaosGoW]

Yeah honestly from hearing about potential headaches of 3 way SLI, I really want to like it, but i'd only go for it if i had more money to burn. Maybe next build i'll go with a ridiculous 4 way SLI setup just for fun. I really want to see 3 way and 4 way SLI supported like 2 way is haha. 

I really don't see the need to add a 3rd card atm. 

1. You need a mobo that can do it which requires X99 or a PLX bridge

2. You can't do mATX with 3way

3. I'm already hitting the 144hz cap at 1440p with games maxed with most of the games I play so adding a 3rd wont help at all since g-sync stops from rendering more.

4. I haven't done 4way since I had 2 4870X2s in the same machine and it was CONSTANT BSOD and crashing. It's probably better now but it did leave a sour taste in my mouth

 

All these and more are reasons I wont be doing more than 2way SLI

 

Spend the extra money you would have spent on a super nice case and some watercooling gear. It's way more fun to build a watercooled rig than you'll get out of a 3rd card.

[Speedbird]

I've got a 1440p 144hz screen (asus ROG Swift) and have been considering two highly overclocked aftermarket 980s or three reference 980s to try to push as close to 144fps in as many games as possible which is why i'm interested in Sli since theres no single graphics card that will satisfy my FPS-lust

The ROG Swift has G-Sync, so you don't have to lock at 144 fps. A single overclocked 980 is good enough.

[NumeroSieben]

The ROG Swift has G-Sync, so you don't have to lock at 144 fps. A single overclocked 980 is good enough.

 

It's not about "locking" it there, but getting the average frame rate as close to 144fps as possible so gsync can do its thing, but right at the upper limit of the monitor's power. a single 980 simply isnt strong enough to push that kind of framerate even overclocked at 1440p. It's the goal of my build. Also i want headroom for DSR in even demanding current titles

[MrGoat]

I had SLI GTX 280s, and GTX  460s in SLI for a bit. Both experiences have turned me away from SLI forever. Not only is the extra performance rarely actually utilized, a lot of games (MWO still!) don't support sli, and for games have very poor sli profiles where they can actually run worse than a single card. Also I had a lot of microstuttering issues with the 460 SLI set up, nothing but an absolute headache trying different beta drivers and frame rendering options just for a little bit of improvement in on certain games, only to end up with more issues in the end than it is worth. It just isn't worth the price of an entire second graphics card, imo. A single card will always be the best cost value and you should never run into all the issues that come with trying to run in SLI mode. But of course YMMV, I have heard sli is better now days, but I am hesitant because I keep reading about the exact same issues.

 

 

a single 980 simply isnt strong enough to push that kind of framerate even overclocked at 1440p. It's the goal of my build. Also i want headroom for DSR in even demanding current titles

For me it most certainly is. Granted I haven't tried a lot of the newest console port games, but I haven't found a single game that the gtx980 can't at least run above 100fps in 1440p. In most everything I play it is 144fps constantly.

[D2ultima]

I had SLI GTX 280s, and GTX  460s in SLI for a bit. Both experiences have turned me away from SLI forever. Not only is the extra performance rarely actually utilized, a lot of games (MWO still!) don't support sli, and for games have very poor sli profiles where they can actually run worse than a single card. Also I had a lot of microstuttering issues with the 460 SLI set up, nothing but an absolute headache trying different beta drivers and frame rendering options just for a little bit of improvement in on certain games, only to end up with more issues in the end than it is worth. It just isn't worth the price of an entire second graphics card, imo. A single card will always be the best cost value and you should never run into all the issues that come with trying to run in SLI mode. But of course YMMV, I have heard sli is better now days, but I am hesitant because I keep reading about the exact same issues.

I can guarantee you that SLI is a lot better these days, though it isn't without its problems. If you ever try to do it again though, let it be because the single most powerful GPU isn't enough for you .

[D2ultima]

hey everyone,

 

i'm considering a 2 way or 3 way SLI setup. I'm aware 2 way is actually pretty well supported in general but 3 way has a lot more issues, scaling problems etc. So i wanted to ask what these problems are actually like. Can i not launch the game? If i can launch the game, will it use 1 graphics card only with zero SLI support, and 2 cards if it only supports 2 way SLI? 

 

What are the frame problems that 3 way SLI has, i've heard it can cause frame rates being more all over the place, and can also stutter sometimes. Does gsync alleviate this problem?

 

On top of that, is there anything else i should know about 2 way and 3 way SLI?

 

Thanks never had a SLI rig before and i have a lot of money to build a rig that i might be making absolutely ridiculously just because i can soon (3 way GTX 980 sli. Otherwise 2 way is what i'll go with)

Honestly, if there's anything you really want to know about SLI, you can check the guide in my sig (which for some reason isn't stickied yet >_<).

 

As for 3-way, you should be able to force games to use only 2 cards if 3-way scaling is bad, however I've never heard of 3-way scaling being worse than 2-way before (not to say it doesn't exist). Since you're attempting to get 980s in SLI, I'm assuming that the single strongest GPU isn't enough for you, so go right ahead. If worse comes to worst, you could probably use your 3rd card for widescreen gaming or to force obscene levels of MFAA on games (not sure if MFAA works like this; I know CSAA does. I don't have 980Ms to test myself unfortunately).

[NumeroSieben]

Honestly, if there's anything you really want to know about SLI, you can check the guide in my sig (which for some reason isn't stickied yet >_<).

 

As for 3-way, you should be able to force games to use only 2 cards if 3-way scaling is bad, however I've never heard of 3-way scaling being worse than 2-way before (not to say it doesn't exist). Since you're attempting to get 980s in SLI, I'm assuming that the single strongest GPU isn't enough for you, so go right ahead. If worse comes to worst, you could probably use your 3rd card for widescreen gaming or to force obscene levels of MFAA on games (not sure if MFAA works like this; I know CSAA does. I don't have 980Ms to test myself unfortunately).

 

That's a really helpful post! it should be stickied and thanks for the input. So lets say i have a game that only supports a 2 way SLI and doesn't benefit from the addition of a third card, i can use the nvidia control panel to force the third GTX 980 to force that MFAA or CSAA to make it look nicer without the third card going to waste? This might really re-invigorate my interest in a 3 way SLI setup as it costs not all that much more than the 2 way (1670 AUD vs 2100 AUD). My main gripe with the third card when i look is when i will and wont be getting benefits from it.

 

I'm really interested in the BEST visual experience possible, and i've chosen 144hz 1440p on max settings as my goal on as many games (and into the future) as possible, and using techniques like DSR (which is effectively a version of anti aliasing as i understand it) to then further enhance the quality of games that i have performance overhead to still get the huge frames per second levels. 

 

What's the differnece between forcing MFAA and CSAA by the way?

[D2ultima]

That's a really helpful post! it should be stickied and thanks for the input. So lets say i have a game that only supports a 2 way SLI and doesn't benefit from the addition of a third card, i can use the nvidia control panel to force the third GTX 980 to force that MFAA or CSAA to make it look nicer without the third card going to waste? This might really re-invigorate my interest in a 3 way SLI setup as it costs not all that much more than the 2 way (1670 AUD vs 2100 AUD). My main gripe with the third card when i look is when i will and wont be getting benefits from it.

 

I'm really interested in the BEST visual experience possible, and i've chosen 144hz 1440p on max settings as my goal on as many games (and into the future) as possible, and using techniques like DSR (which is effectively a version of anti aliasing as i understand it) to then further enhance the quality of games that i have performance overhead to still get the huge frames per second levels. 

 

What's the differnece between forcing MFAA and CSAA by the way?

As far as I know, CSAA is disabled on Maxwell chips, so you won't be able to use CSAA. MFAA should be okay. Alternately, you could use your third card as a PhysX card or something.

 

MFAA is a different kind of Anti-Aliasing. It uses very efficient multisampling techniques to use multisample anti-aliasing. Apparently only maxwell is capable of doing the calculations.

CSAA is nVidia's "more efficient" form of MSAA. It can go far higher than MSAA will (I've seen 16x AA in ONE GAME: CoD Black Ops 1; every other time it caps out at 4x or 8x) all the way up to 32x CSAA on a single card and 64x CSAA using SLI.

 

Some people claim that there is no visual difference between 8x MSAA and 16xQ CSAA or 32x CSAA. In some games like Titanfall I find that to be the case. In others like Killing Floor, I find it to be beneficial to use 32x CSAA.

 

I wish I could answer more about how Maxwell GPUs work in SLI, but as I stated in my guide, unless someone is willing to send me a pair of 980Ms, there's no way I can do this. Alternately someone could buy me a desktop with two 970s, but I'd need a full desktop (monitor, keyboard, etc) so that's even less cost effective.

 

Next, I don't know how forcing MFAA works, or how many games support it. I know forcing CSAA in some games doesn't work all that well. I know Skyrim will crash if I do it, but it'll accept forcing 16x Anisotropic filtering. So you need to experiment there. I will say though that if you want 1440p 144Hz max graphics in all games, 3-way 980s are not exactly a bad idea. Especially in a year or two, you'll probably be glad you have them.

 

OH. And I hope you're using an extreme intel CPU with enough PCIe lanes to support 3 980s. A consumer GPU won't support it unless the motherboard has a feature built in for it, and even then I am told it does not work as well as in-built PCIe lanes.

[NumeroSieben]

As far as I know, CSAA is disabled on Maxwell chips, so you won't be able to use CSAA. MFAA should be okay. Alternately, you could use your third card as a PhysX card or something.

 

MFAA is a different kind of Anti-Aliasing. It uses very efficient multisampling techniques to use multisample anti-aliasing. Apparently only maxwell is capable of doing the calculations.

CSAA is nVidia's "more efficient" form of MSAA. It can go far higher than MSAA will (I've seen 16x AA in ONE GAME: CoD Black Ops 1; every other time it caps out at 4x or 8x) all the way up to 32x CSAA on a single card and 64x CSAA using SLI.

 

Some people claim that there is no visual difference between 8x MSAA and 16xQ CSAA or 32x CSAA. In some games like Titanfall I find that to be the case. In others like Killing Floor, I find it to be beneficial to use 32x CSAA.

 

I wish I could answer more about how Maxwell GPUs work in SLI, but as I stated in my guide, unless someone is willing to send me a pair of 980Ms, there's no way I can do this. Alternately someone could buy me a desktop with two 970s, but I'd need a full desktop (monitor, keyboard, etc) so that's even less cost effective.

 

Next, I don't know how forcing MFAA works, or how many games support it. I know forcing CSAA in some games doesn't work all that well. I know Skyrim will crash if I do it, but it'll accept forcing 16x Anisotropic filtering. So you need to experiment there. I will say though that if you want 1440p 144Hz max graphics in all games, 3-way 980s are not exactly a bad idea. Especially in a year or two, you'll probably be glad you have them.

 

OH. And I hope you're using an extreme intel CPU with enough PCIe lanes to support 3 980s. A consumer GPU won't support it unless the motherboard has a feature built in for it, and even then I am told it does not work as well as in-built PCIe lanes.

At the moment if i get triple GTX 980 i have to go with the motherboard option as upgrading to a motherboard that supports 3 and 4 way SLI with a 4790k CPU is FAR cheaper than stepping up to an x99 and an extreme edition CPU. I might try to shop around and see if i can get things any cheaper but my $3800 (4800 including the ROG Swift monitor) budget actually struggles thanks to Australian prices. (and the lack of overseas shipping options).

 

I asked and one person who responded said there was "negligible difference" between a PLX motherboard and having genuine in build PCI lanes in the CPU but i was still leaning back towards two 980s instead because of the extra expenses versus the rewards but your posts have interested me a lot so i think i'll try to work out a version with a 5820k to drive 3 980s if possible. That and i didn't particularily trust the very small response from someone who may or may not have known what they were talking about. Genuine pci lanes are much preferable to me as well.

 

I'm always hoping to see more sli support over time too haha. I dont think i'd ever build a PC without SLI ever again because i am not a reasonable person. i want the overkill options because i spend so much time either working on the PC or playing games on it that it doesn't make sense not to buy the best.