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680s, 780s, Titans

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Paul King
680s, 780s, Titans
on Jun 6, 2013 at 10:13:01 am

Hi All

Here comes that same question again re GPUs.
I have to deliver a new Resolve system.
It will be based on the Supermicro board and the client wants to do 4k.
So to do 4k you need 4 x 680 @ 6000 CUDA cores.

I would like to be able to give them 2 x Titans @ 5400 CUDA cores or 3 x 780 @ 6900 CUDA cores. These two options are much better suited to avoid an expansion chassis. The question is how many CUDA cores are needed for 4k? Obviously more than 4500 as that's how many you get from 3 x 680.

Problem is that the configuration has not been updated and I know Davinci have not tested the 780 yet, so can anyone give me their own empirical advice on Titan performance? Also can anyone from Davinci tell me if the 3GB of RAM on the 780 is enough for 4k?

Thanks in Advance


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andrew smith
Re: 680s, 780s, Titans
on Jun 6, 2013 at 2:27:50 pm

Would this be Hackintosh, Linux or PC? Just curious as I am thinking of what my own next build will be post-WWDC disappointment.


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Paul King
Re: 680s, 780s, Titans
on Jun 6, 2013 at 2:59:14 pm

Hi Andrew

PC - Win 7.

WWDC disappointment?


Thanks




Paul



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Juan Salvo
Re: 680s, 780s, Titans
on Jun 6, 2013 at 3:07:10 pm

Counting cores is not a good way of measuring performance between GPUs. It's very much an apple to oranges comparison.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Paul King
Re: 680s, 780s, Titans
on Jun 6, 2013 at 4:18:28 pm

Hi Juan

Well this holds true for the 690, however my question was in context of RAM on each card. Peter from Blackmagic has already informally qualified the Titans, but the issue here is we have no info on how many are require for 4k work.

All we have so far is 4 x 680s for 4k.
I'm simply asking how many 780s and how many Titans.
Maybe I'll be the first guy to find out if no one else knows.
But this has become a significantly important question now that we have new GPUs available in 2013. An expansion chassis has always been a very expensive option and only serves to house what will become redundant technology.

Thanks




Paul



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Joseph Owens
Re: 680s, 780s, Titans
on Jun 6, 2013 at 6:25:54 pm

[Paul King] "An expansion chassis has always been a very expensive option and only serves to house what will become redundant technology."

My hope is that an expansion chassis is as beneficial as the cards housed in it, and those can be changed as technology evolves. So if two Titans equals 4x690s, then does 4 Titans = 8 690s? I don't think the math works that way, but 8 GPUs would always be a non-starter for Resolve/Mac no matter what, so the expansion option should remain a viable option for massive processing for some time.

jPo

"I always pass on free advice -- its never of any use to me" Oscar Wilde.


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Juan Salvo
Re: 680s, 780s, Titans
on Jun 6, 2013 at 7:46:22 pm

One Titan does not equal one 690... much less two. Roughly speaking 1 Titan = .85 690s. Or 1.40 680s.

But that's an incomplete evaluation.

Let me just say this. If cost is no object just use Titans. As many as you can. And always use an expansion chassis. Trying to use multiple GPUs (more than 2) on a mother board can be very frustrating.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Al Arnold
Re: 680s, 780s, Titans
on Jun 6, 2013 at 9:26:04 pm

I've been running 3 GTX 580s + Decklink card in a single Windows 7 system/chasis for a year or so without issue. Running a beefy PSU, and huge case though. Cooling, configuration and noise can definitely be issues, but if addressed much more affordable than an expansion chasis.


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Juan Salvo
Re: 680s, 780s, Titans
on Jun 6, 2013 at 11:14:44 pm

I've seen behavior vary from manufacturers to manufacturer, and between card models, and firmware updates. It works for you, thats great. But by and large, there tend to be issues with multigpus directly on the motherboard, where there are few within the expansion chassis. Better all around to just get an expansion chassis.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Paul King
Re: 680s, 780s, Titans
on Jun 7, 2013 at 12:19:43 am

OK

I take it from the responses that not many here have enough experience with this hardware.

Win/Mac limit 4 GPU, so bigger expansion chassis makes no difference.
Titans in the release versions all come from the one factory so no variation between manufacturers for the moment.

I take it you guys are all Mac guys (with the one exception).
The Supermicro board is specified by Davinci for the purpose of multiple GPUs. The notion that GPUs work better in an expansion chassis doesn't make sense as rhe expansion chassis has less bandwidth than the motherboard.

If there are formulas bandied around such as 1.4 x 680 then the question is relevant comparing CUDA cores. Blackmagic here in Australia have said so to us, they just haven't released any testing results with the newer GPUs.

It makes no sense to put in as many Titans as possible as they are expensive and there is obviously a limit to the number of CUDA cores required for 4k. My question was how many - 4 x 680 = 6000 cores.

Dont want to seem too ungrateful for the replies but they're not very helpful for the original question.


Thanks




Paul



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Juan Salvo
Re: 680s, 780s, Titans
on Jun 7, 2013 at 1:21:49 am

Hi Paul,

[Paul King] "Win/Mac limit 4 GPU, so bigger expansion chassis makes no difference."

Actually the GPU limit on Macs is 5. I happen to run both Mac and Linux.

[Paul King] "Titans in the release versions all come from the one factory so no variation between manufacturers for the moment."

Sure but the question and discussion wasn't just about Titans. And there is also the issue of motherboard manufacturers.

[Paul King] "The Supermicro board is specified by Davinci for the purpose of multiple GPUs."

Why don't you take a look at the config guide? They still spec an expansions chassis for anything more than 2 GPUs.

[Paul King] " The notion that GPUs work better in an expansion chassis doesn't make sense as rhe expansion chassis has less bandwidth than the motherboard."

Well "better" can mean a lot of things. I meant it as in more stable and reliable. As in all the cards show up in the os between boots. As far as the issue of shared bandwidth, which has been brought up before, it's not a factor thanks to clock sharing.

[Paul King] "If there are formulas bandied around such as 1.4 x 680 then the question is relevant comparing CUDA cores. "

No, that's precisely the wrong comparison. Even NVidia will tell you, the number of cores alone is not a good indicator of performance. My multiplier is based on my own tests with those cards.

[Paul King] "It makes no sense to put in as many Titans as possible as they are expensive and there is obviously a limit to the number of CUDA cores required for 4k. My question was how many - 4 x 680 = 6000 cores."

You want to talk expensive, spec out a config with K5000s. Actually Titans makes great sense for a bunch of reasons. One is the amount of RAM onboard the card which is a factor today, but will be an even bigger factor tomorrow. Again the number of cores is not what you want to be counting. But go right ahead and do as you like.

Best of luck to you.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Robbie Carman
Re: 680s, 780s, Titans
on Jun 7, 2013 at 2:08:36 am

Just to reinforce a couple things Juan has mentioned....

Mac can now with latest OS and drivers def. do 5 cards. I'm running it now. Couldn't get it to work at first SMC reset has done the trick.

Like Juan, in a Super Micro PC as well as a RAIN system, I had trouble with more than 2 cards on the mother board and boots etc. Seems like the gaming systems with 3 or 4 cards are working SLI which Resolve doesn't support. Cubix has been the only thing thats worked in reliable fashion and yes the bandwidth thing is NOT an issue thanks to clock sharing - data is passed to the card and the clock sharing ensures data is passed off from the card to the bus in separate intervals thus each card works at full bandwidth

Also the thing with cores etc etc. Its all about card design in balance with the application. Just look at something like SpeedGrade vs Resolve. SpeedGrade is built around quadro cards. Resolve works best with GTX cards. A while back everyone was hot to trot on Q4000 and they were WAY slower than GTX cards that cost half as much and probably had less cores!. Its a balance for sure

Finally, gotta say I've been relying on Juan for years about NVIDIA GPUs from here on the COW and other places. He is a beta tester and and works closely with NVIDIA. I always default to his opinions and notes regarding NVIDIA GPUs. He's 99.9% right about GPU performance.

Robbie Carman
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Margus Voll
Re: 680s, 780s, Titans
on Jun 7, 2013 at 8:52:17 am

It tends to boil down to what someone have heard or dreamed.

Taking good advice is not for everybody as my friend says. (he is in hi end server business)

I would also go with Juans ideas as he has the experience.

--

Margus

http://iconstudios.eu
https://vimeo.com/iconstudioseu/videos

DaVinci 9, OSX 10.7.4
MacPro 5.1 2x2,93 24GB
GTX 470 / Quadro 4000
Multibridge 2 Pro


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Al Arnold
Re: 680s, 780s, Titans
on Jun 7, 2013 at 10:20:43 pm

Using an ASUS P9X79 WS Mobo for my PC Config. (Also have a Mac Pro w/ 210+570) You can disable SLI in the NVIDIA settings, and resolve does see all three GPUs. Honestly, you could just pull the link cable, but I like to leave it on so I can game on it occasionally. Thank God NVIDIA added the ability to disable SLI in software! At work we run Linux resolve with the 8 GPU expander attached to the Super Micro chassis, so no help there. I'm guessing that that specific motherboard & PSU can't handle more than two GPUs reliably. Only trying to point out that if going the DIY route that it is possible to run a stable 3 GPU system.

Agree with Juan that simply counting CUDA cores is not a gauge of performance. Would an AMD 4 core vs Intel 4 core CPU comparison at identical clocks yield equal performance? Nope! There is a reason why 580's still compare favorably to the current gen NVIDIA gaming GPUs in CUDA performance even though they have far fewer CUDA cores: Focus on gaming performance over compute when engineering the new GPUs. I Understand the reasoning (More people use their products to play games than compute), and it just validates what Juan is saying.

http://www.anandtech.com/show/5699/nvidia-geforce-gtx-680-review/17

http://www.tomshardware.com/reviews/geforce-gtx-780-performance-review,3516...


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Paul King
Re: 680s, 780s, Titans
on Jun 8, 2013 at 3:52:57 pm

Frankly everything said here has been inconsistent and at times conflicts with Resolve published information.

The official config says 1 x GPU use 680, 2 x GPU use 680 or 1 x 690 (although they are not recommended due to a lack of RAM - they are still on the list for 4k) 4 x GPU use 580. So they don't recommend 680 for 4 x GPU. Problem with the config is they say what to do but not what not to do (same here in this thread). They say use MB for 2 x GPU and expander for 4 x GPU but not why that is. As far as Davinci are concerned, more than 2 x GPUs are not recognised, however we have Al here saying that they can be.

Also, config says going from 1 x GPU to 2 x GPU is a double in performance (doubling of CUDA cores). It also says don't use Quadro unless you have to as GTX is far better performance. So why? All that they have over Quadros is CUDA count. Look at the new Quadros, doubling of CUDA cores. Why?

Nvidia could not justify the price hike for Quadros and give us a bunch of marketing speak as to why they are better. But here we are with one of the most professional and GPU intensive apps in the industry and consumer cards are recommended.

When it comes to CPU, if I double the core count or the speed I get a equivalent increase in render performance. However this is only in an app that can make use of multiple CPUs. So if you ask me the question about doubling CPU cores, I can answer it concisely, but qualified by the particular application being used. So the same Q relating to AE is a little bit more complicated.

All I have from this thread is cryptic answers. Nothing here has been useful for building a Davinci in June 2013, except Als suggesting about multi GPUs and the SLI setting.

BTW Al you can compare AMD and Intel CPUs, we always could knowing the architecture and I was always able to explain it to someone. But it's a moot point now as AMD will new catch Intel in the performance space.



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Margus Voll
Re: 680s, 780s, Titans
on Jun 8, 2013 at 8:26:27 pm

But you are right on the money here that it is not 1:1 way to go here.

It all depends on so many aspects.

--

Margus

http://iconstudios.eu
https://vimeo.com/iconstudioseu/videos

DaVinci 9, OSX 10.7.4
MacPro 5.1 2x2,93 24GB
GTX 470 / Quadro 4000
Multibridge 2 Pro


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