No speed gain? Corona vs V-ray GPU/CPU

[rye_fanoni]

Hi, I'm doing some testing with V-ray as I will need to use it on some future projects. But I've been very suprised to see no speed gain over Corona no matter which method I use.

My system is modest but capable: RTX 2070 super, Threadripper 2950X, 128 RAM. Running latest versions of Corona and Vray in Cinema4D R21.

The test scene is coming in at a little over 2.5 minutes in corona and roughly 3.5 in Vray. I tried progressive and bucket in CPU - RTX and cuda in GPU. None of these options got down to the Corona time.

Is this expected behaviour? Or is there something I should be changing somewhere? Render settings are pretty much the defaults (which is fine these days apparently).

[sirio76]

Setting Vray and Corona to produce similar results is far from easy, there are hundreds of settings that may affect speed and quality on both.
You need to know very well the engines and set them up to use similar technology (as far as possible) and it's not a trivial task. Once you have done that you will get similar results (both speed wise and aesthetically), from my tests Corona tend to load scenes slightly faster while Vray tends to favor larger scenes quite a bit.
Comparing Vray CPU and GPU is the same, they are literally two different engines so you will get similar results but not 1:1.

[rye_fanoni]

Thanks Sirio. Naturally you'e correct in that there are many things that I could change. But nevertheless I'm still pretty suprised. By the GPU speed especially.
The default settings should give a reasonable result time and quality wise IMHO. There are no complex items in the scene.

[sirio76]

Overall Vray default settings are good and are what I use except for the denoiser (I use the Intel) and the effect refresh rate (I use 100% to get faster feedback).
Displacement default are not optimal IMO, probably they have choose those to be on the save side but I tend to use very different settings that are quite a bit faster and vastly more efficient.
Probably you are disappointed by the GPU speed because marketing have promoted for years GPU engines that are 10/100/1000 time faster than the CPU engines in order to sell more graphic cards, real world speed is a different thing though and GPU engines are usually a bit faster but never that much, sometime depending on the scene a CPU engine can even be faster (comparing he same range of CPU and GPU).

[aleksandar.kasabov]

Hello rye_fanoni,

As Sirio mentioned above, V-Ray and V-Ray GPU are two different engines and their performance shouldn't be compared by simply switching from one engine to the other as the results won't be accurate. When comparing both engines it is recommended to use scenes that are optimized for the specific engine.

We have prepared an article that offers a comparison between the V-Ray and V-Ray GPU render engines. Please have a look at it here and let us know if you have further queries. Thanks.

[rye_fanoni]

Hi Aleksander.
"When comparing both engines it is recommended to use scenes that are optimized for the specific engine."
I've taken a look at the article you linked. But there really isnt much info there about optimising scenes for specific engines. Just general info about the difference between GPU/CPU rendering. As there is no dedicated GPU material or lights - what exactly are these optimisations I should be taking on a simple scene? (I know translucency isnt supported for instance - but that's just a limitation).

[stefan_laub1]

i recommend also testing a more complex scene. there differences will be more visible. in such a tiny scene scene loading/preparing etc will take quite some %, not cpu/gpu or engine type.

on a side note: for me corona is amazing fast,even on cpu and huge scenes, v-ray cpu a tiny bit slower but has more features. both very good