Question / Help 1080ti's SLI: Best way to use them?

[Storx]

Hello All,

I currently already own a pair of 1080ti's in SLI from my mining days. I have been thinking of trying out streaming since I already play multiple games on a regular basis on a 1440p monitor and someone mentioned that I could use my GPU to offload the streaming encoding. Can I use my 2nd GPU for this since most games it's not fully utilized?

I attempted to stream with a test using some of the presets for twitch, I found it was killing my system pegging my CPU to 100% and causing the gaming to be unplayable..

 

[Narcogen]

Sure!

Put it in a 2nd PC.

Any other configuration is going to create a bottleneck on your PCI bus. You can't effectively separate rendering/encoding functions on separate cards without creating such a bottleneck that makes performance worse than a single card configuration, and OBS doesn't even work well with SLI.

The best way to utilize a 2nd strong GPU is to put it in another PC, and connect those two machines either with a capture card or via a network with the OBS NDI plugin.

 

[Storx]

Sure!

Put it in a 2nd PC.

Any other configuration is going to create a bottleneck on your PCI bus. You can't effectively separate rendering/encoding functions on separate cards without creating such a bottleneck that makes performance worse than a single card configuration, and OBS doesn't even work well with SLI.

The best way to utilize a 2nd strong GPU is to put it in another PC, and connect those two machines either with a capture card or via a network with the OBS NDI plugin.

Thank you for the reply,

How much of a loss or pain in the butt is it to use the GPU in SLI still? I ask this because most of the modern games I play it still helps to some degree on the FPS... I game in 1440p and I found it adds 20-30% more fps to the game placing most games just over the 144fps threshold with all the graphic settings fully turned on how I like it to allow me to fully use my 144hz monitor.

I am planning on upgrading my system within the next few weeks, I was researching the reviews on the new Zen 2 CPU's, was leaning on upgrading my 3570k to the new 3900x to hopefully keep me happily gaming for the next 5+ years as the 3570k has.

Do you think the 3570k system could be recycled and turned into a dedicated streaming 2nd pc? or is the 3570k to weak to be used in this manner?

 

[Narcogen]

Yes, I think a 3570 would be acceptable, if you're going to use the hardware encoder on the GPU in that machine. I use a 3770 in a machine dedicated to this task.

 

[Storx]

Hmm,

So the 3570k cant do it on its own? just making sure i understand fully. My computer case is a dual system case and was thinking of buying a used m-ITX motherboard for the 3570k if it was able to process the NDI code and stream it for me on the 2nd machine.

What would be a minimal CPU to do this then? I was reading a build someone did on a dual system setup and he went with a AMD 2200G as his 2nd pc CPU for his dedicated streaming box.

 

[Narcogen]

No. If you put the 3570 by itself the only encoder you have is QuickSync, and if you are willing to use that instead of the better hardware encoder in your GPU, you can do that without a 2nd PC at all.

Your question was about SLI, so what I'm saying is-- don't do that. OBS doesn't work well with SLI, and there's no way to effectively use a 2nd powerful GPU in a single machine. The best use of a 2nd powerful GPU is in a separate machine connected to your first machine either by a capture card or via NDI over gigabit ethernet. So if you are going to have a new CPU, the best configuration is:

3900X
1080ti

3570x
1080ti

With a capture card or ethernet gigabit between them. A machine with the 3570x alone can't run NVENC and can't render particularly well or run a game particularly well.

A machine with two 1080ti will either 1) not run any better than a machine with one 1080ti because you're ignoring it, or 2) run worse than a machine with one 1080ti because you're trying to either run SLI or separate rendering and encoding.

 

[Storx]

No. If you put the 3570 by itself the only encoder you have is QuickSync, and if you are willing to use that instead of the better hardware encoder in your GPU, you can do that without a 2nd PC at all.

Your question was about SLI, so what I'm saying is-- don't do that. OBS doesn't work well with SLI, and there's no way to effectively use a 2nd powerful GPU in a single machine. The best use of a 2nd powerful GPU is in a separate machine connected to your first machine either by a capture card or via NDI over gigabit ethernet. So if you are going to have a new CPU, the best configuration is:

3900X
1080ti

3570x
1080ti

With a capture card or ethernet gigabit between them. A machine with the 3570x alone can't run NVENC and can't render particularly well or run a game particularly well.

A machine with two 1080ti will either 1) not run any better than a machine with one 1080ti because you're ignoring it, or 2) run worse than a machine with one 1080ti because you're trying to either run SLI or separate rendering and encoding.

Thank you for explaining it more to me. I was under the impression when people had 2nd systems for streaming they didn't need a GPU because the few builds I read I didn't see a 2nd GPU listed. It almost sounds like the 3570k is not worth spending the money to run as a 2nd rig in streaming and I should maybe just do a single pc setup and maybe sell the 2nd 1080ti and try to get as much as I can for the 3570k off eBay for the new PC build. It just sucks, because I've had such great success with SLI in gaming in the more recent games I play with 2k res...

Random question, not sure how much hardware is needed for the 2nd pc encoding, how effective would a Quadro NVS 295 GPU be at encoding? The reason I ask this is the Corsair 1000D case I have is designed for 2nd PC installed internally, but after looking at a few builds, I didn't see any with full-size GPUs, most just have smaller single card slot GPUs and not sure how much hardware is needed for 1080p60 streaming.

I'm currently going to wait a little longer till September at least to make my decision on my pc build, the reason behind this is the new 3950x is suppose to launch then and I'm curious of how it will perform come its release with the software side of things maturing with the launch of Zen 2. There has been a lot of talks that the benchmarks of the 3900x have been flawed to a small degree due to scheduling issues still in Windows. A few people have posted results between benchmarking gaming on the 3900x normally vs forcing the game to run on a single CCD chiplet using 6 core/ 6 threads only and most are showing improvements of up to 22% gain in fps in some games doing this, basically testing out the chiplets and figuring out which chiplet is the stronger of the 2 and forcing the games on that chiplet and all other task on the other chiplet. With these results popping up and level1tech showing that threadripper is still needing more work on the scheduler in windows 1903 build, it sounds like the support to fix this issue is kinda on the back burner still even with the new zen 2 launches. With the above results in mind the 8/8 chiplets on the 3950x may be a stronger option to extend to for gaming as many newer titles are starting to fully use 8 cores properly optimized with the support behind the 9900k and its payed staff...

Im thinking it may be in my best interest to sell my 2nd 1080ti GPU and stick to a single GPU and drop the extra money on the new 3950x coming out in a few months to give myself a more capable rig for streaming, gaming, and video rendering.... we may even get news on the 3rd gen threadripper, as the recent leaks of 32 core and 64 core chips maintaining the same single core benchmarks as the zen 2 current released chips. I understand i really dont need all the cores, as gaming is really only needing 6/8 cores right now, but i feel future games are going to use more cores as both intel and amd are both pushing the more cores theme and all those cores will give me the ability to render videos better.

 

[Narcogen]

The advantage of Quadro cards generally is that they don't have limits on the number of NVENC sessions. The GPU on the 2nd machine still has to render all frames prior to encoding, though, so that needs to be considered as well. But just as an encoder, it should be no problem.

Is the problem that the 100D case doesn't have a 2-slot wide area for a GPU, or isn't long enough for a full length card?

 

[Storx]

The advantage of Quadro cards generally is that they don't have limits on the number of NVENC sessions. The GPU on the 2nd machine still has to render all frames prior to encoding, though, so that needs to be considered as well. But just as an encoder, it should be no problem.

Is the problem that the 100D case doesn't have a 2-slot wide area for a GPU, or isn't long enough for a full length card?

The positioning of the ITX motherboard places it extremely close to the side panel when the kit guru was building his rig he had to go with water cooling on the ITX GPU because when running on air it was running very warm with it positioned within a few mm of the side glass.

Also, I was asking about the Quadro card because I am not sure how strong of hardware is really needed to meet the 1080p60 stream standard that most seem to run these days. The use of the 2nd 1080ti in the 2nd system just seems like complete overkill, so if the job can be done with far less of hardware id prefer to sell off the GPU and put that money into the main rig.

What really confuses me is I have googled 2 system streaming builds, I have come across multiple rigs that the 2nd system doesn't list a GPU, with most going with iGPU CPUs on the 2nd system. Is it that newer CPUs are powerful enough to x264 encode?

 

[koala]

The quality of the x264 "veryfast" preset is about the same as the quality of nvenc on the GTX 10x0 cards. This is some kind of break even point. If you have a CPU that is able to handle a better preset than veryfast, such as faster, fast or medium, you create better quality with x264. This is mostly true for streaming PCs where there is no game to run at the same time. Most better desktop CPUs are able to achieve this.

With the new RTX 20x0 cards, the nvenc encoder was improved. It is said its quality is between fast and medium x264 preset. The break even point has shifted with that, so it is often better to just use a single desktop PC for gaming and streaming at the same time and use nvenc instead of x264. OBS explicitly supports a single PC setup with the nvenc (new) encoder, which avoids copying raw video data over the pci-express buss. This is true for every nvenc system, not only RTX setups.

Now let's talk about the GPU in the streaming PC. OBS still needs a minimum amount of GPU power to composite the video. Only with trivial scene setups and small canvas, an iGPU is able to handle this. For a more sophisticated setup with multiple sources, multiple scenes and the usage of filters, most iGPUs are overloaded. For such a setup, you need a "real" GPU even on a streaming PC. Your additional 1080 Ti is somewhat overkill, but it is not completely wasted in a streaming PC because of this.

The best price/performance ratio for a pure streaming PC was the GTX 1050 because of the nvenc encoder in case the CPU wasn't able to handle more than x264 veryfast. However, with the phasing in of the new RTX 20x0 and GTX 16xx cards with Turing chip, one might look for a newer version of a low-cost, yet somewhat powerful GPU. For some reason, I don' recommend AMD GPUs, but I might be biased. It's mostly because of the nvenc encoder, which is unmatched by the AMD VCE hardware encoder.

 

[Narcogen]

The 1660 is probably the sweet spot for anyone who doesn't require they pay bottom dollar for a card-- it's got the encoder chip from the 20xx series without the cost or the ray tracing.

 

[Storx]

The quality of the x264 "veryfast" preset is about the same as the quality of nvenc on the GTX 10x0 cards. This is some kind of break even point. If you have a CPU that is able to handle a better preset than veryfast, such as faster, fast or medium, you create better quality with x264. This is mostly true for streaming PCs where there is no game to run at the same time. Most better desktop CPUs are able to achieve this.

With the new RTX 20x0 cards, the nvenc encoder was improved. It is said its quality is between fast and medium x264 preset. The break even point has shifted with that, so it is often better to just use a single desktop PC for gaming and streaming at the same time and use nvenc instead of x264. OBS explicitly supports a single PC setup with the nvenc (new) encoder, which avoids copying raw video data over the pci-express buss. This is true for every nvenc system, not only RTX setups.

Now let's talk about the GPU in the streaming PC. OBS still needs a minimum amount of GPU power to composite the video. Only with trivial scene setups and small canvas, an iGPU is able to handle this. For a more sophisticated setup with multiple sources, multiple scenes and the usage of filters, most iGPUs are overloaded. For such a setup, you need a "real" GPU even on a streaming PC. Your additional 1080 Ti is somewhat overkill, but it is not completely wasted in a streaming PC because of this.

The best price/performance ratio for a pure streaming PC was the GTX 1050 because of the nvenc encoder in case the CPU wasn't able to handle more than x264 veryfast. However, with the phasing in of the new RTX 20x0 and GTX 16xx cards with Turing chip, one might look for a newer version of a low-cost, yet somewhat powerful GPU. For some reason, I don' recommend AMD GPUs, but I might be biased. It's mostly because of the nvenc encoder, which is unmatched by the AMD VCE hardware encoder.

Based on my understanding of your reply, it sounds like you recommend I just stick to a single PC setup and upgrade my GPU to an RTX based GPU. Am I understanding this correctly?

Based on your comment on using CPU x264, would the new AMD 3900x be powerful enough to encode since it seems the GTX1080ti is equivalent to x264 very fast on CPU. Im seeing reports of people getting better results on gaming with the AMD 3900x by locking the game to use a single CCD chiplet (6cores/6threads) vs the entire chip, which would leave an entire another half of the CPU to be available to other tasks.... maybe encoding??? Example given on forums: 3900x using all cores with PBO, Battlefield V average FPS of 153, but when they locked the game to only using the 6 cores on the 2nd CCD on the CPU, they saw average FPS increase to 171 due to scheduling issues in windows trying to cross the infinity fabric instead of prioritizing use of a single CCD before pulling from the other chip...

Also while doing some reading on the use of NDI in OBS, I read its best to send the monitor's native resolution as the NDI resolution source to the 2nd PC, then downscale encode it to 1080p60 for least loss of FPS drop in gaming and least amount of CPU usage on the gaming rig. So in my case, I want to use my 1440p@165hz monitor for a gaming rig, so I would send 1440p source to 2nd pc, then convert to 1080p to send to stream aka twitch?

The 1660 is probably the sweet spot for anyone who doesn't require they pay bottom dollar for a card-- it's got the encoder chip from the 20xx series without the cost or the ray tracing.

So if I am understanding this correctly, it sounds like the RTX GPU is an upgrade over the 1080ti I have currently in regards to encoding on the stream pc (2nd)?


Lastly, I want to ask these questions..... If I was to pursue the 2 PC streaming setup.....

1) what is like the minimal CPU that could actually encode 1080p60 on its own without a GPU, ask this because I'm seeing a lot of people dumping 1st and 2nd gen Ryzen hardware right now. Last night I saw an AMD 1700 for sale on eBay go for $81 shipped.. and an auction on an AMD 1900x threadripper CPU end at $117 shipped. Unsure how much CPU power would be needed for CPU only encoding....but maybe a single CPU/Mobo setup would be the cheaper route....???? The benefit of this route if better would be i could use m-itx mobo in my system and since they only come with 1 single PCIE slot, I could use a 10GB NIC, since I've read its highly recommended for NDI encoding.

2) Doing a little reading and research, I came across EposVox who went the route of Quadro Card for GPU encoding. He mentioned in his setup that the minimum hardware needed for his goal according to Nvidia matrix sheet was the 1050ti, but couldn't find one for a reasonable price at the time of his testing/purchasing, but he found a brand new Quadro P400 for around $100. In his testing, he stated he was able to encode with it 1080p@60 "high quality".... so not really sure where that stacks up on the chart for stream encoding compared to let's say the 1080ti, since he mentioned the Quadro is more efficient at doing encoding vs a typical GPU..... I ask this because there are a handful of P400 cards used selling in the $35-50 range on ebay.

 

[koala]

Based on my understanding of your reply, it sounds like you recommend I just stick to a single PC setup and upgrade my GPU to an RTX based GPU.

Single PC setup - yes.
Upgrade GTX 1080ti to RTX - if you want to throw your money at this, yes. A GTX 1080Ti is still a decent GPU that usually does not need a replacement unless you feel the urge to always run the latest and greatest hardware.

Based on your comment on using CPU x264, would the new AMD 3900x be powerful enough to encode since it seems the GTX1080ti is equivalent to x264 very fast on CPU.

Probably yes. Depends on the game that is running, but I don't think there is a game that uses so much cores that there are nothing left for x264 encoding. The 3900x/3950x seem to be the most powerful consumer CPU ever, and at the same time not being vastly overpriced as the corresponding Intel ones. They are a real hit. Even their single thread performance finally seems higher than on Intel, which is the real relevant benchmark value for games.

But before you buy, wait and look for benchmarks and user reports how this power works out in real applications.

I am unable to comment to ndi, since I don't use this myself and didn't pay attention to what is written about it in the forum. I assume it would be best to downscale on the gaming pc to the resolution you intend to stream on the streaming PC, because with 1440p@165 there is so much raw data to transfer, your network may be too slow for that, even it it was gigabit. Sending and receiving this much data also stresses the I/O systems of both machines very much. Downscaling on the GPU needs almost no resources, while transferring huge raw data does.

 

[Storx]

Single PC setup - yes.
Upgrade GTX 1080ti to RTX - if you want to throw your money at this, yes. A GTX 1080Ti is still a decent GPU that usually does not need a replacement unless you feel the urge to always run the latest and greatest hardware.

Probably yes. Depends on the game that is running, but I don't think there is a game that uses so much cores that there are nothing left for x264 encoding. The 3900x/3950x seem to be the most powerful consumer CPU ever, and at the same time not being vastly overpriced as the corresponding Intel ones. They are a real hit. Even their single thread performance finally seems higher than on Intel, which is the real relevant benchmark value for games.

But before you buy, wait and look for benchmarks and user reports how this power works out in real applications.

I am unable to comment to ndi, since I don't use this myself and didn't pay attention to what is written about it in the forum. I assume it would be best to downscale on the gaming pc to the resolution you intend to stream on the streaming PC, because with 1440p@165 there is so much raw data to transfer, your network may be too slow for that, even it it was gigabit. Sending and receiving this much data also stresses the I/O systems of both machines very much. Downscaling on the GPU needs almost no resources, while transferring huge raw data does.

Thank you for explaining things more for me to understand. I am going to wait for the release of the 3950x come to this September, I have a feeling the prices of mobo for the x570 boards will settle down some and become more reasonable... also that will give a few months for bugs to get worked out of the bios and hardware with the new ryzen cpu's. There is rumor of threadripper being released at the same time as the 3950x, so maybe that will be an option also, because there has been leaks of both a 32 core and 64 core threadripper chip and if the 32 core is $1,000 or less I may swing for it... and build a high-end single pc setup and plan to upgrade my GPU on the next launch of Nvidia GPUs... i have a feeling Nvidia is going to drop something better than the RTX2080ti pretty soon...

 

[Storx]

What is yalls opinion on this? I only ask this, because I reached out to E I was planning to upgrade my gaming rig and try to get into streaming and he recommended a completely different route than what I was looking to go.... He said for pure gaming nothing can touch the value of the 9700k overclocked to 5.0+ Ghz, not even the 9900k, because apparently, the spectrum meltdown patches caused a lot of slowdown on the 9900k due to its hyperthreading...

He is recommending the following:

Game Rig:
Intel 9700k
1080ti (1 or 2 in SLI)
16GB Ram
M.2 Nvme

Stream Rig:
Intel 3570k (test it after the upgrade)
HD60Pro Capture Card
Quadro NV295 or iGPU (already own, for monitor display only)
16GB Ram (already own)
SSD (already own)

He mentioned as a new streamer going the route of the 9700k would give me the best gaming setup for just pure gaming if I decide to not stream or just want to record gaming instead of streaming...

In regards to the streaming PC, he mentioned to me that it would be best for me to use a capture card, because then if I truly want I can then use both of my 1080ti's and use the capture card to bypass the issues related to SLI.

Also he mentioned that he is not positive, but he thinks the 3570k may have enough CPU power to encode for 1080p streaming, he is truly not sure as he has never tested this before, but he helped someone set up a streaming pc with an AMD 1200 CPU and it had just enough processing power to encode at 1080p with capture card setup and the 3570k is roughly around the same level as the AMD 1200... So after i purchase the stuff to upgrade the gaming rig, stick the old mobo, cpu setup on the desk and bench test what it can do for encoding. If its able to perform to the task, then either shove it in a cheap pc case or get an itx mobo and install it in my main setup....he recommended the 2nd pc case, because itx cards lack PCIe slots and if i want to do HD game recording, adding a cheap GPU to the streaming rig would be better than using the CPU.

Basically, he is saying for streaming, CPU encoding produces a better picture on the stream and for game capture/recording a GPU produces a better picture for 1440p+ recording, so recommended a cheap $60 1050ti

 

[koala]

This forum might not be the best place to collect and discuss machine setups. It's about using OBS Studio, a software. Hardware is a completely different topic. The only thing that can be said about hardware from OBS' point of view: The strength of OBS Studio is operating on a single PC setup where you use game capture to stream a game. If you optimize your system around this premise, you get the most benefit while requiring the least money. This is only true where you are able to use game capture. Capturing a console requires a capture card and the paradigms shift.

Which hardware exactly you will use depends on your wallet and on the technical development. I always try to give generic answers - answers that are true even 2 years later. So instead of recommending some GPU or CPU, I point to 2 benchmark websites where you can compare the computing power of these components: https://cpubenchmark.net/ and https://www.videocardbenchmark.net/ . To estimate cost and compute price/performance ratios, you have to consult your favorite dealer/retailer. There are ratios on these benchmark sites as well, but the prices are not the prices I get on the german market where I live, so their ratios are off.

If I design a new PC for me, which takes place about every 3-5 years, my research takes about a week. It includes not only the above, but also test and comparison reports on the web. My process is to first define what kind of stuff I intend to run on the hardware and with which quality. Then I look and find eligible hardware, making a huge list of possible alternative components. The list covers every component I intend to put into the PC. It is based on marketing info, technical specifications and price. The rest of the research is about eliminating items from the list until only the best matching item for every component is left, which is what I buy and assemble in the end.

If such work is too much for you, consult an expert and rely on his expertise.