SLI Advice, GPU Cooling Advice

[Hockster]

@Hockster that is a beautiful build mate. I still think you would have been better off with a single 1080 ti though. then sell the 1080 ti a month or so before release of 2080 ti, and pop her in. thats my plan anyway, even if it means taking a few hundred dollars loss every year, its what i always do. I require ultimate power! ONE PUNCH MAN! GO! Minion Rider Cycles for Justice!

Thanks.
I had one 1080 at launch, way back when prices were sane. Adding a second one was cheaper than going with a Ti when I upgraded my monitor to an ultrawide.

 

[Vayra86]

If you want my advice, stay clear of SLI these days.

- Support is getting much less prevalent, a few years ago that trend started and its not changing
- The mainstream GPUs already lack SLI fingers = it is rapidly becoming a very tiny niche
- Devs don't optimize for tiny niche
- Scaling limitations eliminate most of the cost advantage
- Its extra heat in the case, marginalizing the overclock on the top GPU, which will also reduce the potential of the bottom one
- Pascal is heavily temperature affected as an architecture, so a hot card will directly influence boost clocks in a pretty significant way.
- SLI adds input lag
- SLI adds higher frame time variance
- SLI destroys the perf/watt

 

[HuLkY]

If you want my advice, stay clear of SLI these days.

- Support is getting much less prevalent, a few years ago that trend started and its not changing
- The mainstream GPUs already lack SLI fingers = it is rapidly becoming a very tiny niche
- Devs don't optimize for tiny niche
- Scaling limitations eliminate most of the cost advantage
- Its extra heat in the case, marginalizing the overclock on the top GPU, which will also reduce the potential of the bottom one
- Pascal is heavily temperature affected as an architecture, so a hot card will directly influence boost clocks in a pretty significant way.
- SLI adds input lag
- SLI adds higher frame time variance

Thanks man, that was so detailed, I wonder why developers still couldn't get round all these difficulties, a game like Witcher 3 almost scaled 90-100% with nVidia cards.

 

[Vayra86]

Thanks man, that was so detailed, I wonder why developers still couldn't get round all these difficulties, a game like Witcher 3 almost scaled 90-100% with nVidia cards.

Its never 100% because there is always overhead, and you also lose another 5-10% of the total performance due to lower boost clocks.

But yes, some games can scale really well and the performance you have under the hood at that point is pretty awesome. I just like my gaming hassle free... and from my experience of owning 2x GTX 660 back in the day, it was anything but that. It was hot, it was loud(er), and I did come across several games that didn't get proper support. If you play a wide variety of games, stay FAR away. If all you play is triple-A stuff, then the experience will be a bit better. Another consideration is the balance between VRAM/bandwidth and core power. The latter doubles, but the first does not and without proper frame capping / sync you will have stutter.

If the choice is ever between 'a single top tier card' versus 'two of a lower tier' - always go for the single. If its about adding another GPU after a while because you feel you lack performance, be very wary of your target resolution and whether the VRAM can handle that.

EDIT: since DX12 developers are supposed to add multi GPU support themselves for the most part as well. This doesn't help either... Nor do multiple APIs (we now have Vulkan as well, and DX11 is going to be around for awhile too).

 

[neatfeatguy]

Its never 100% because there is always overhead, and you also lose another 5-10% of the total performance due to lower boost clocks.

But yes, some games can scale really well and the performance you have under the hood at that point is pretty awesome. I just like my gaming hassle free... and from my experience of owning 2x GTX 660 back in the day, it was anything but that. It was hot, it was loud(er), and I did come across several games that didn't get proper support. If you play a wide variety of games, stay FAR away. If all you play is triple-A stuff, then the experience will be a bit better. Another consideration is the balance between VRAM/bandwidth and core power. The latter doubles, but the first does not and without proper frame capping / sync you will have stutter.

If the choice is ever between 'a single top tier card' versus 'two of a lower tier' - always go for the single. If its about adding another GPU after a while because you feel you lack performance, be very wary of your target resolution and whether the VRAM can handle that.

EDIT: since DX12 developers are supposed to add multi GPU support themselves for the most part as well. This doesn't help either... Nor do multiple APIs (we now have Vulkan as well, and DX11 is going to be around for awhile too).

Everyone's experience tends to differ when it comes to SLI/Crossfire.

Personally, based on my past experiences with it and what I see coming down the pipe I have a different appreciation for SLI than you do. I, however, have a similar look at the future of it.

I ran SLI with the following cards over the past dozen years or so:
7600 GT
8800 GTS 640MB
8800 GTS 512MB
GTX 280
GTX 570
GTX 980Ti

Rarely did I run into issues after the 8800 GTS 512 cards. Before that, there were a lot of games that had poor support or just really odd issues that no driver would fix. I don't recall the 3rd party program that I'd have to run and then it would allow a lot of tweaking of settings (kind of what you see when using the Manage 3D Settings in the Nvidia Control Panel these days) to help fix odd issues. One issue I vividly recall when running the 8800GTS cards in SLI was during The Witcher - light sources in the game would brightly shine through walls. Torches or the sun would shine through background drops (trees and such) or through walls in buildings. If I disabled SLI the issue went away. I had to use the 3rd party program to fix the lights bleeding through when SLI was enabled.

Sure, I'd come across a game or two that just wouldn't run with SLI enabled. No big deal, just disable it and be on my way to gaming after about 30 seconds. Some games didn't see performance increase with SLI. Some games didn't utilize SLI. Some games saw great boost in performance with SLI while most games gave a good/decent performance increase under SLI.

Sure, the top card ran hotter - usually 10C on average. And the power draw was higher, but I loved SLI. I could buy one high-end card and usually after 6-8 months later I could pick up a second one at a much cheaper price point. Then I'd have a system that would outperform a single top-tier card or a system that would still provide solid performance if SLI support was lacking or not working (which in my experience was a rarity).

With DX12 on the horizon (let's face it, games aren't flying off the shelf that only support DX12 yet) and having the developer being responsible for enabling multi-gpu support.....I just don't see the developers naturally going this route. Plus with only top-tier/high end cards supporting SLI these days, I don't think most people should worry about going SLI in the future. I believe that the 9xx series was the last series to make good use of SLI.

 

[HuLkY]

Everyone's experience tends to differ when it comes to SLI/Crossfire.

Personally, based on my past experiences with it and what I see coming down the pipe I have a different appreciation for SLI than you do. I, however, have a similar look at the future of it.

I ran SLI with the following cards over the past dozen years or so:
7600 GT
8800 GTS 640MB
8800 GTS 512MB
GTX 280
GTX 570
GTX 980Ti

Rarely did I run into issues after the 8800 GTS 512 cards. Before that, there were a lot of games that had poor support or just really odd issues that no driver would fix. I don't recall the 3rd party program that I'd have to run and then it would allow a lot of tweaking of settings (kind of what you see when using the Manage 3D Settings in the Nvidia Control Panel these days) to help fix odd issues. One issue I vividly recall when running the 8800GTS cards in SLI was during The Witcher - light sources in the game would brightly shine through walls. Torches or the sun would shine through background drops (trees and such) or through walls in buildings. If I disabled SLI the issue went away. I had to use the 3rd party program to fix the lights bleeding through when SLI was enabled.

Sure, I'd come across a game or two that just wouldn't run with SLI enabled. No big deal, just disable it and be on my way to gaming after about 30 seconds. Some games didn't see performance increase with SLI. Some games didn't utilize SLI. Some games saw great boost in performance with SLI while most games gave a good/decent performance increase under SLI.

Sure, the top card ran hotter - usually 10C on average. And the power draw was higher, but I loved SLI. I could buy one high-end card and usually after 6-8 months later I could pick up a second one at a much cheaper price point. Then I'd have a system that would outperform a single top-tier card or a system that would still provide solid performance if SLI support was lacking or not working (which in my experience was a rarity).

With DX12 on the horizon (let's face it, games aren't flying off the shelf that only support DX12 yet) and having the developer being responsible for enabling multi-gpu support.....I just don't see the developers naturally going this route. Plus with only top-tier/high end cards supporting SLI these days, I don't think most people should worry about going SLI in the future. I believe that the 9xx series was the last series to make good use of SLI.

So there is no point in making a SLI out of a GTX 1080 Ti or Titan Xp for example, right?

 

[neatfeatguy]

So there is no point in making a SLI out of a GTX 1080 Ti or Titan Xp for example, right?

It's kind of hard to say. Personally I'd say no unless you have the money to spend or are a firm believer you'll get good use out of the setup. This current gen (10xx series) I'd suggest getting one of the highest card you can afford and playing games within the limits of the card. Once tech moves on or perhaps SLI appears to be getting solid support again, then look into the idea of SLI.

Games coming out in DX9/10/11 are still handled on the driver level for SLI and that falls into Nvidia's lap. Any game that are DX12 (which things are slowly shifting into) are handled on the coding level from the developer. If they don't enable multi-gpu in their game, SLI/Crossfire won't work. Last I looked, 6 months back or so, I think it was only around 8 or 10 games that have multi-gpu support on DX12 titles (https://en.wikipedia.org/wiki/List_of_games_with_DirectX_12_support). I'm not sure how up to date that list is, but that's where I got my info from.

 

[HuLkY]

Games coming out in DX9/10/11 are still handled on the driver level for SLI and that falls into Nvidia's lap. Any game that are DX12 (which things are slowly shifting into) are handled on the coding level from the developer. If they don't enable multi-gpu in their game, SLI/Crossfire won't work. Last I looked, 6 months back or so, I think it was only around 8 or 10 games that have multi-gpu support on DX12 titles (https://en.wikipedia.org/wiki/List_of_games_with_DirectX_12_support). I'm not sure how up to date that list is, but that's where I got my info from.

so now it's up to the game developers more than before to see an actual gain from SLI or CF?

 

[John Naylor]

As indicated above ... something strange has happened with SLI that goes beyond developers and support. Twin 970s were 40% faster than the 1080 for the same price.... the more demanding games ... the ones everyone wanted to play ... were in the 90s with a few breaking 100% in some tests (makes no sense). Average scaling was 70%; when a game didn't support SLI, you were already getting 85 fps so what's the big deal getting 10% more from the 1080 ?. But where one 970 gave you 42 fps and the 1080 and the 48 ... twin 970s was giving you 75 fps in AAA games. So it was there when ya needed it... and when it wasn't there, you didn't need it.

Now with the 10xx series, average scaling is just 18% at 1080p and 33 % at 1440p... and yet oddly enough > 50% at 4k. What's going on ? It's almost as if, recognizing no competition from AMD if the SLI capable price niche, nVidia was trying to set prices and performance such that consumers would no longer see a price / performance advantage w/ SLI.... and the sensible buy would be the higher priced 1080 / 1080 Ti card which generated a larger profit margin than the two x70s.

If AMD can produce a performance / power / price competitive card next generation, ... with the same scaling that we used to see, I wonder if SLI performance will suddenly improve again.

 

[RealNeil]

So there is no point in making a SLI out of a GTX 1080 Ti or Titan Xp for example, right?

I have one 1080Ti card (MSI GTX-1080Ti Gaming-X Trio) and it doesn't seem to need another. But it's not a stock-clocked card.
Make no mistake, If I had the cash, there would be another one right below it.
I'm waiting for my next two cards (Gigabyte 8GB Gaming G-1 GTX-1070Ti cards) to be delivered to me. They'll go together in my i9-7900X build.

 

[Melvis]

Well I just got Vermintide 2 this week since it was on sale for 25% off and I heard that it does support SLi. At first when I ran the game SLi didnt work and was only running on one card, but after I updated the Nvidia Drivers SLi was working and it went from Medium settings at 1440P to Extreme settings at 1440P, getting around 40-70FPS, so im pretty happy about that with my SLI GTX970's. Thought id let you know

 

[FreedomEclipse]

I too used SLi and CF for yeeeeeeeeeears.

Radeon 4870CF
Radeon 5850CF
Radeon 6970CF
GTX680 SLi
GTX970 SLi

Given the direction that Nvidia and game developers were going with optimising for multi-gpu configs, i decided to drop SLi all together to save compatibility issues with future games. I do miss seeing 2 GPus stacked up next to each other though.

YMMV depending on your setup -- you may run high res or refresh rate monitors so need/want a multi-Gpu config but for an average joe like me, It just wasnt worth pursuing no more.

 

[adulaamin]

Will a 4790k @ 4.7 bottleneck 2 1080TIs when gaming on an Acer Predator X34P? I'll hang on to the 4790k if I still can but if I need to replace it I will. I was really hoping for the 8086K to be 8C/16T but it's not!

 

[RealNeil]

What's going on ? It's almost as if, recognizing no competition from AMD if the SLI capable price niche, nVidia was trying to set prices and performance such that consumers would no longer see a price / performance advantage w/ SLI....
If AMD can produce a performance / power / price competitive card next generation, ... with the same scaling that we used to see, I wonder if SLI performance will suddenly improve again.

We were getting great SLI performance results with mid-level GPUs from NVIDIA, but they disabled SLI on the low/mid level 10 series cards when they came out. They purposely screwed the market up to force us into spending more money for our fun.
Imagine a pair of GTX-1060 6GB cards in SLI working properly. That's where a hell of a lot of us would have landed. Yet I had to pay more on two of my systems because of their actions.
GTX-1070s and GTX-1070Ti cards run great in SLI. I love them, but 6GB GTX-1060s would have done the deed for much less cash.

As far as responding to AMD's possible innovations, yeah they could crank out a few "special edition" card designs on short notice. They probably have the SLI enabled designs tested and burned-in when/if they need them.
Like Intel two years ago, they're far too comfortable with their dominance.

 

[er557]

Will a 4790k @ 4.7 bottleneck 2 1080TIs when gaming on an Acer Predator X34P? I'll hang on to the 4790k if I still can but if I need to replace it I will. I was really hoping for the 8086K to be 8C/16T but it's not!

IMHO it will bottleneck them, especially with cpu intensive games, like recent AAA titles. What is your refresh rate and do you game vsynced?

 

[adulaamin]

IMHO it will bottleneck them, especially with cpu intensive games, like recent AAA titles. What is your refresh rate and do you game vsynced?

The X34P is 120hz and is a g-sync monitor. The games I currently play are SC2, Civ 5/6, The Witcher 3. After 2 years of mostly working away from home, I've got around a month of free time coming up so I will be buying a few more games. It's my first time using more than 1 GPU and based on what I've read here, it must have been a mistake but I've already got the parts so I'll just see for myself I guess.

 

[er557]

maybe a drop in used replacement for the cpu?

 

[RealNeil]

Try it out. You're gonna like it

 

[adulaamin]

Try it out. You're gonna like it

Will the 4790k bottleneck at 3440×1440 though? Is it a big enough bottleneck that I need to change my mb, cpu, ram?

 

[Space Lynx]

Will the 4790k bottleneck at 3440×1440 though? Is it a big enough bottleneck that I need to change my mb, cpu, ram?

at that resolution no. your gpu bottleneck will hit first in most games before the cpu matters too much...

 

[er557]

gpu bottleneck at 120hz and sli 1080ti? those cards are beast, need faster cpu

 

[adulaamin]

gpu bottleneck at 120hz and sli 1080ti? those cards are beast, need faster cpu

Maybe i I was on a lower res it would be? As the resolution goes up you'll stress the CPU less?

 

[Hockster]