Here is the answer to your question, Corona is brand new, built from the ground up with the latest and greatest. Look at the speed and quiality of it’s GI engine, plus it’s simplicity, shader system, even though it takes longer to clean final render it’s still very fast for what it is. Imagine all of that running on the power of GPU or assisted on the GPU. I believe Ondra has built a fantastic CPU renderer, and would love to see it be better. That’s all… and why not.
1 TEST: 19x
1 TEST: 23x
1 TEST: 10x
1 TEST: 11x
1 TEST: 19x
1 TEST: 17x
I’m sure that, soon or later, Corona will be CPU+GPU (in some way).
Right now, it’s better to be concentrate to add a new features on PCU version.
This is actually what we are trying to do, but hey, I am programming renderers only for 6 years, and those green-black marketing slides from hardware companies have to be at least a bit correct, right?
And I was a little thrown over to the fan:
CPU is sad. AMD not give us in last 3 ears not one good cpu. Intel in terms of good jump on 2600k then on 4770k (or 3930k someone - that) and now 5820k. And this is in shot words 5 ears of life. And they don give us posibility to use several cpu’s on one MB, even xeon - 2 cpu for MB is this standard version is above all more expensive so that it is easier to use DR. All other options is one - DR but for DR for each cpu we must have another MB, another 32gb ram, another SSD+HDD, another PSU.
BUT for 4 very fast gpus for example need only two powerful PSU that it.
Good example https://www.youtube.com/watch?v=CZ1IRQTqMMY and https://www.youtube.com/watch?v=QFUpPe3o1rE conform this OctaneBench 2025.2 Results • OTOY 8xGTX 580
it is = 4x980 Ti and they easy can stay in one case in sense PSU (2x1000W) and mobo - 4 PCIe its easy, and 980ti have 6gb vram. And again - look on speed in video in octane and vray.
I just hope that ondra in a secret from us develop corona on GPU. Even maxwell https://www.youtube.com/watch?v=6VHzONYfgUg think about gpu 
And some more videos for GPU+corona vote (i hope Ondra already see they all) - in description render time\per frame
and if they give to users even 75% of what they promise here
OTOY • OTOY unveils OctaneRender 3: Massive upgrade to the world’s best GPU renderer defines the state of the art for VFX in films, games and beyond it’s strange that Ondra not interested in gpu and again I just hope that ondra in a secret from us develop corona on GPU.
Ondra, why are you getting defensive? You are taking this the wrong way, we think your brilliant programmer for what you have done with corona. Why do you keep bringing up marketing slides or papers on the subject to dissuade us when we are telling you with real world tests the gpu is much faster for interactive setting up a scene to final rendering. So far every scene I have worked on testing with cpu and gpu, there is no question that gpu is X times faster. What will happen to this great renderer you created when next year Pasal comes out and all the other renderers have full GPU support for all features. No matter how great corona is, people will move on if the render time goes from 4hrs, to just a few minutes. and not even the fact of cost, gpus are cheap compared to the optional cpus.
Here what is great about GPU cost.
1 Titan X is X times faster than the best CPU. Now for just $999 more you can add another Titan X reducing render times by half again. And we all know most systems will house 4 GPUs. And with pci risers you can put up to 8x GPUs.
compare that to the cost of one system that can barley compete with one Titan X. then multiply the cost of each new complete system you have to buy.
We’re using Corona for 2+ years for production and all this time we’re had no doubs that it was right choice. Rendertimes was a bit higher than Vray, but simplicity using of Corona complitely outweights it. But now we have a big project with huge number of images to render at high resolution and render times becomes a bottleneck in pipeline. As we tested Corona and even IrMapped Vray has nothing to do with it. But our test revealed solution in VrayRT GPU as it is a 3x times quiker for the same money (42x i7-4790k roughly the same speed as 8x GTX 980Ti in two PCs). And much more compact and energy efficiet too (40+ PCs versus only 2 PCs).
Of course it is neede completely new code for GPU, new shaders and so on. I know that even all standart maps has to be completely redone to be rendered on GPU. But it has done in Vray and partially in Octane. GPU is really fast and it has a bright future I think. Even one or two yeras ago we can’t even imagine that graphics card under $1000 can have 12Gb of memory. Since Titan X and introduction of Pascal with up to 32Gb of memory it will be possibe to to really big projects with rendering on GPU without strong memory limitation (that was a main reason to avoid GPUs).
Would like to see the comparison, because the old one Cecofuli posted is deceiving. It’s not Vray vs VrayRT GPU, but VrayRT (CPU) vs VrayRT (GPU), where the engine, is pure BF/BF in both cases.
It just recently received LC algorithm as well, making even VrayRT(CPU) fast, but it’s not fast as regular Vray algorithms.
But given I now have Titan-X as well, I can give it some try.
Just a small test to see GI speed. Lighting from sun and sky only. No portals.
VrayRT GPU (GTX 580)
Bruteforce+Bruteforce = 32 min
Bruteforce+Lightcache = 10 min
Corona 1.0 (i7-3930k@4.1GHz)
PT+UHDC = 27 min
As you can see VrayRT GPU BF+LC already at 10 minutes is clean enough.
Of course it’s not a complex test but one of tests
One more test at scene from Vray’s forum converted to Corona correctly. (of course you can see some differences but I do not think that they have a huge impact in overall speed)
This test was made to know how many time it will take to render same scene as we needed for our project. We see that GTX 580 in VrayRT GPU has done it in 1/3th of time needed to render same scene in Corona on i7-3930k and i7-2600k.
Render times are:
VrayRT - 12 min
Corona - 12 and 29 min
Fobus, thanks for the comparisons, can you post the tea pots scene, I have same processor as you, but I have a Titan X which is much faster than a 580. I’ll run it and post my times for comparison.
Here are scenes done in 3dsmax 2015. I havn’t got Vray so demo version was used as You can see from pictures. So default settings are saved I think. But I made no changes from open to render it so You can simply open it and render with default settings saved (lightcache as secondary GI saved I think)
Update:
I had to check files to upload right versions.
Update 2:
Uploaded right versions of max scenes. Uploaded VrayRT image just rendered in less than 5 min at 2xGTX580 from VrayRT scene.
Update 3:
Uploaded image just rendered from attached scene in Corona 1.0 on i7-3930k@4.1GHz in 15 min
Corona_CornelBox_Test_Fob_03.rar (1.84 MB)
VrayRT_CornelBox_Test_Fob_03.rar (1.88 MB)
I tried your scenes just for fun..
System:
2x Xeon E5-2697 v3
64gb ram
1 Geforce GTX 980
With V-Ray I set the Max paths/pixel to the same amount you had: 20007
With Corona I set the same amount of passes you had: 3962
With my system the V-Ray RT Gpu version was not that much faster.
With Corona 6min 58s and with V-Ray RT Gpu 6min 14s.
This is a great comparison, and when I say great I mean not for the vray. Corona has a more efficient and better GI system. It gets great time in this, this is the type of test corona will excel at more. But remember we are comparing corona CPU to vray GPU, two totally different renderers. Now just imagine what the time would be if it was Corona GPU.
1st image) First is Vray straight comparison, you had two options checked that slow down final render and are only good for fast preview for interactive. - 4min32sec
2nd image) This is with those incorrect settings turned off - 4min6sec
3rd image) this is with just a little 2 second tweak - 3min29sec
1 GTX Titan X, now imagine just adding one more card.
If anyone has a larger more detailed scene to try that would be great to do.
Look at config and You’ll realize that You’re comparing $500 GPU with $5000 CPU and you can easily set up to 4x980Ti in one PC with increasing GPU speed nearly 5x from your GTX 980 in just $3000. So it is really possible to reach speed of 10x Xeon E5-2697 v3 in just one PC cheaper than 2x Xeon E5-2697 v3. Of course It will be only 6Gb of GPU RAM, but we are talking about future and in nearly future there will be much more RAM on GPU (8Gb on mid-end ATI http://www.techpowerup.com/reviews/MSI/R9_390X_Gaming/ on its way and, as was written before, nVidia said that Pascal GPU supports up to 32Gb of RAM)
You have to remember this is also a scene that really favors coronas superior GI engine. Now you take more well lit scenes, or even the everyday scenes I work on and GPU renders much faster. A scene I’m working on for a client right now is a kitchen scene, just for fun I tried both CPU vs GPU. Cpu was 12min35sec, GPU was 2min9sec. and there was no comparison the CPU was much more noisy so it would of taken even longer to clean up.
I’ve got the scene done in Corona Alpha 7.1 a bit optimized for 1.0. Plus the same scene converted to Vray. But I have not Vray 3.2 to render it (demo has so much limitation that makes it impossible to test)
Corona
https://cloud.mail.ru/public/443AVAermhxe/CONF_Test_Corona_01.rar
VRay
https://cloud.mail.ru/public/2GspyBg1jPb9/CONF_Test_Vray_04.rar
I would like to see Juraj to join this conversation about GPU/CPU
He usually have some facts, in one or the other direction that can lead to some note resting data on this regard.
Cheers!
GPUs are growing in compute power much quicker than CPUs in last few years. Scalability is much more efficient. The two major troubles I see at this moment: First for us, users, is a small amount of RAM available to render huge scenes and the Second is for developers - is much more complicated programming for GPUs plus need in completely redone all 3dsmax maps (at least most used) to be compatible for GPUs. The First one is going to be gone in 1-2 years as we see RAM amount are growing fast. So I hope The Second one will not be a barrier to get much more compute power for much more less money.
Do I smell irony :- ) ?
I honestly think GPU is also the future, I was never of opposite opinion, but I was always tired of how it is 10-100x faster, when that obviously never was (I could tell given I had Octane). And all the limits GPU engines had (gets much better today but, it took Octane 5 years, and VrayRT GPU is still in puberty, better than infancy though)
Now I honestly don’t care when and how that gets implemented given the speed-up in actual scenes can be between 3-4x, and my render times would still be few hours (as I know they are for those few GPU studios that are out there, like DeltaTracing guys),
I would still need render-farms like Rebus as I do now. Because that gives me 5 minute renders for few bucks :- ) I surely ain’t buying quad-Titan-X to each in our office when even that won’t suffice, just like Dual-Xeons don’t suffice when I need to finish 5 8k Finals in single day.
For now my Titan-X is purely Unreal engine beast, but I make give a brief go again to see where all that competition is now (Octane/Redshift/etc..) out of interest when time permits.
A little story
As I noted before we’re faced a big problem in rendering of upcoming big project. It contains 2 mins of exterior shots and 3000+ spherical panoramas of interiors. Our little renderfarm is capable to render all exterior shots in time but it will be 100% loaded. As we started to count the time to render 3000+ images with 5k resolution we’re realize that with our lovely Corona it will takes approximately 120 days (4 time more than we have). Of course it is possible to cut rendertimes to 1/4 by decreasing fidelity but this is not our way. Then we’re started research how to cut rendertimes in other way. VRay with Bruteforce+LightCache seems to be a real solution till we done some tests from wich we’re noticed that it is a 1.5 slower than Corona PT+UHDC. IrMap+LC was roughly the same speed as Corona but with poor quality. So VrayRT was the latest option. And it rocks. Even at old GTX 580 it was much faster than on any our rendernode or workstation. Of course it hasn’t got some features from CPU Vray but rendertime was great. So as our farm will be busy all the time we’re startetd calculations with options of buying new regular PCs for Corona based rendering, buying GPUs and rendering on external renderfarm. Numbers (rough): Rebus renderfarm - $20000 (400Hrs on 100PCs), Regular PCs - $45000 (30 days on 35PCs!!!) and $9000 for GPU PCs (2PCs with 4x980Ti). As our little farm contains only 16PCs adding 35PCs will kill our energy cables and conditioners. Administration of this huge number of PCs is terrible too. 400Hrs for rendering versus 30 day is delicious but it is wasted $20000.
Cheers