Why Does 1080p Bottleneck SLI (How to get 120fps at 1080p)

[kayaknate]

I am using an Asus monitor with Lightboost via ToastyX. This gives a crystal clear picture if I am able to push out as many frames as the backlight strobes per second. Right now I have a 780 trying to push out 100 fps. I can achieve this in most games with mostly high and some ultra settings. I would like to go all out ultra at 120fps though.

Newegg is having a clearance on 780s at $360. Amazing price. I've already purchased one as I didn't want them to run out before I learned about this. I've read a few times that 780s in SLI bottleneck with 1080p. Can someone elaborate on this? If this is the case, how do I push out the amount of frames I want? One would think that SLI would be the solution, but with this bottlenecking at 1080, I'm not sure it would be.

 

[COLGeek]

What other components are you using to make up your rig (CPU, motherboard, memory, etc)? Your issues could be some other component. Please clarify.

 

[Spencervde]

Some people encounter CPU bottlenecking, meaning that their CPU is choking the GPU and making it not perform as well. Power supplies can be a downer too, if the power supply is a bit lower than required or doesn't have enough leeway, the GPU will become underpowered causing bad things. Some games may have a FPS cap as well, I play CS:GO and it caps me out at 300FPS on Max Settings.

 

[Traciatim]

I wish peopel would erase bottleneck from terminology used for describing computing scenarios.

The problem is that if you increase your performance by 60-90% over your existing 100FPS you'll be pushing 150-190FPS, which means you can't even display that many frames on your monitor. That means it's a 'bottleneck' of sorts because one item is slower than the other item. What it also means is taht you can turn up things like your AA settings which impact your maximum frame rates much more than your minimums or you can use V-Sync to avoid tearing without impacting your perceived performance since if you can pull 190FPS and your AA settings drop your performance by 20% you'll still be above what your monitor can even output.

In essence you'll still get better visual quality with more consistent performance.

 

[kayaknate]

My configuration:
Asus VI Hero
Core i5 4670k OC to 4.4
16GB RAM
EVGA 780 SC
Corsair TX650 (This will need to be upgraded for SLI)

Interesting answer Traciatim. So you are basically saying that bottleneck is the wrong word all together. It's not that 1080p causes an issue were the cards can't perform, rather it's that they are performing amazingly but you can't tell because a typical display will only put out 60fps anyways. So SLI 780 would actually benefit from my situation. Am I understanding you correctly?

 

[17seconds]

These charts show what they mean by being bottlenecked by your monitor's resolution. The scaling, or the improvement over a single card, improves as you increase the monitor resolution. In these charts, there is a 28% improvement by adding a second card at 1920x1200, versus 36% at 2560x1600.

All that says is that you get more value for your money at higher resolutions. But since you have a specific FPS target of 120, then adding another card is really the only way to achieve that. By increasing your graphics settings, you can mitigate some of the bottlenecking by placing more load on your graphics cards. Luckily, those GTX 780 prices are really outstanding, nearly half off the price of just a few months ago.

http://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_780_SLI/21.html

 

[kayaknate]

These charts show what they mean by being bottlenecked by your monitor's resolution. The scaling, or the improvement over a single card, improves as you increase the monitor resolution. In these charts, there is a 28% improvement by adding a second card at 1920x1200, versus 36% at 2560x1600.

All that says is that you get more value for your money at higher resolutions. But since you have a specific FPS target of 120, then adding another card is really the only way to achieve that. By increasing your graphics settings, you can mitigate some of the bottlenecking by placing more load on your graphics cards. Luckily, those GTX 780 prices are really outstanding, nearly half off the price of just a few months ago.

So this was more along what I originally had thought. Better resolution=better SLI performance. So since I'm only using 1080 and just trying to get more frames, am I not going to benefit from SLI as much?

 

[photonboy]

*Long story short is that getting another GTX780 will increase your frame rates. That's all you care about. Since your CPU is unlikely to be a bottleneck, then you should see up to about 80% improvement in some games though it varies quite a lot as you likely know. If you got a 50% improvement and had 100FPS before you'd end up with 150FPS.

 

[17seconds]

These charts show what they mean by being bottlenecked by your monitor's resolution. The scaling, or the improvement over a single card, improves as you increase the monitor resolution. In these charts, there is a 28% improvement by adding a second card at 1920x1200, versus 36% at 2560x1600.

All that says is that you get more value for your money at higher resolutions. But since you have a specific FPS target of 120, then adding another card is really the only way to achieve that. By increasing your graphics settings, you can mitigate some of the bottlenecking by placing more load on your graphics cards. Luckily, those GTX 780 prices are really outstanding, nearly half off the price of just a few months ago.

So this was more along what I originally had thought. Better resolution=better SLI performance. So since I'm only using 1080 and just trying to get more frames, am I not going to benefit from SLI as much?

Yes, that's exactly the point. However, those charts are a combination of 16 different gaming benchmarks. Each game will offer better or worse scaling. You can go through the individual benchmarks to see that there are games that still deliver that ideal 80-90% scaling improvement, even at the lower resolution. Others, generally less demanding games show lower levels of scaling.


Crysis 3 with 83% scaling:

Skyrim, 0% scaling:

 

[kayaknate]

I wish peopel would erase bottleneck from terminology used for describing computing scenarios.

The problem is that if you increase your performance by 60-90% over your existing 100FPS you'll be pushing 150-190FPS, which means you can't even display that many frames on your monitor. That means it's a 'bottleneck' of sorts because one item is slower than the other item. What it also means is taht you can turn up things like your AA settings which impact your maximum frame rates much more than your minimums or you can use V-Sync to avoid tearing without impacting your perceived performance since if you can pull 190FPS and your AA settings drop your performance by 20% you'll still be above what your monitor can even output.

In essence you'll still get better visual quality with more consistent performance.

Thanks!!! This was also very helpful. And you are right, bottlenecking is a terrible way to describe it. It puts a negative connotation on something that is actually a performance increase.