Coming from Blender E-Cycles, VRAY GPU rendering seems very slow in comparison.

[joseph_sorensen]

I haven't yet created a benchmark scene to test both, but my impression after using E-Cycles RTX (a custom build of Cycles designed to fully take advantage of RTX GPUs) is that VRay is much slower. I am kind of underwhelmed. I have Vray 5 GPU as my main render engine in Max and in the performance section of the settings I have my RTX 2080TI selected (RTX, not CUDA).

I really like the quality of VRay, as it excels at many things Cycles doesn't. Caustics comes to mind. But it's just so damn slow. I downloaded a simple wardrobe scene from 3DSky.org and after opening, the Viewport IPR took nearly 20-30 seconds to converge on a decent looking image. Is this par for the course?

I also haven't yet figured out if this is possible yet, but in Blender E-Cycles, you can enable OptiX denoising in realtime. This is a huge improvement and almost completely eliminates grain and noise as you are working. Is this possible with VRay 5?

Would love to hear any feedback from you all, especially those of you that work with both Blender and MAX.

[^Lele^]

Without any image to measure the noise of, or a mention of active settings, you may (stress on the conditional) have tested defaults.

If, as such, you're asking if we are generally slow, the answer to that is a resounding no: our routines are measurably quick, and generally compare favourably with the competition, when doing the same amount of work.
Further, if you just did a first render, you'd have been waiting for the Kernels to compile, which happens only the first time, and that can take upwards of 30 seconds on some computers.

We've got three denoiser types (ours, Optix, and Intel's) , one of which works also in multi-frame scenarios, and they can be toggled provided the proper render element has been added to the scene setup (contrary to others, we do not automatically add REs/AoVs to one's render unless the user initiates the two-clicks operation.).

To my knowledge, however, there is no public version of Blender for V-Ray 5 out yet, so you must have been testing with 3.7, which is ancient (well pre-2.8 ), against a very new tech.
If instead you are trying out V5 under Max, it's an apples to pears comparison, because Max's own architecture is wildly different from Blender's and has pros and cons which do not easily overlap.

If you have anything specific which you think is slow, please contact support and provide them with files, so that they can either find the slowdown and ask for a fix to the devs, or cure the set-up issue in the scene provided so it renders quickly.

Feature-wise, you're welcome to the docs, they have plenty of info and some tutorials to sink one's teeth in (Blender's as old as the version, ignore it.) before committing to even downloading a demo for a specific DCC app.

At some point in the near future, we'll be ready to release V5 for blender as well, and you'll finally be able to test and compare to your heart's content.

[joseph_sorensen]

Further, if you just did a first render, you'd have been waiting for the Kernels to compile, which happens only the first time, and that can take upwards of 30 seconds on some computers

I wasn't waiting for the kernels to compile, I'm aware that this has to be done at first render.

To my knowledge, however, there is no public version of Blender for V-Ray 5 out yet, so you must have been testing with 3.7, which is ancient (well pre-2.8 ), against a very new tech.

I was not testing Blender for V-Ray, I was testing E-Cycles vs V-Ray 5 for 3DS Max.

Apologies for such a generally negative post, I'll do more concrete performance testing later. And that's great news to hear V5 is coming for Blender.

[^Lele^]

Yeah, sorry if the reply sounded harsh, too.
Upwards and onwards, soon it'll be easy to test V-Ray 5 properly from within Blender.

[M.Max]

From what I have read and watched I think E-Cycles takes many shortcuts like clamping and reduce GI/reflection /refraction bounces to save time.
Also it use Nvidia Denoiser for faster viewport which you can enable for VRay too if you would like to.
On the other hand VRay GPU use BF +BF for IPR which is slower to clean up, but more responsive.
Hopefully soon we will have light cache working with GPU IPR too.
Try to do a production render (not interactive) and see if it is still too slow.

[joseph_sorensen]

Yeah, sorry if the reply sounded harsh, too.
Upwards and onwards, soon it'll be easy to test V-Ray 5 properly from within Blender.

No problem. I'd love to know what you guys have planned for Blender integration. Having VRAY 5 fully integrated in Blender 2.91+ would be a dream come true.

[joseph_sorensen]

From what I have read and watched I think E-Cycles takes many shortcuts like clamping and reduce GI/reflection /refraction bounces to save time.
Also it use Nvidia Denoiser for faster viewport which you can enable for VRay too if you would like to.
On the other hand VRay GPU use BF +BF for IPR which is slower to clean up, but more responsive.
Hopefully soon we will have light cache working with GPU IPR too.
Try to do a production render (not interactive) and see if it is still too slow.

Yes, E-Cycles does take advantage of various optimizations that are not physically correct, but in most situations it's not very noticeable. There is also a physically correct preset that's still faster than vanilla Blender. I'm able to render a fairly complex interior scene on a single RTX 2080TI in only 20-30 seconds, and with the new AI denoising included in E-Cycles it's crazy the quality you can achieve in such a small amount of time. I still like the quality of VRay a lot better than Cycles though. Especially when it comes to caustics and glass.

Edit: How do you enable the Nvidia denoiser in real time? Can the IPR use it?

[^Lele^]

No problem. I'd love to know what you guys have planned for Blender integration. Having VRAY 5 fully integrated in Blender 2.91+ would be a dream come true.

Yes, the plan and work is for a full integration.
It's just not trivial, and needs the time it needs to be done right.

Edit: How do you enable the Nvidia denoiser in real time? Can the IPR use it?

Add a denoiser Render Element, choose the NVidia denoiser.
In the render settings, set the Post Effects Rate to 100 (meaning, update for each render pass.), and you're set.
Wether you'll render in a viewport IPR, or in the VFB, or even for Final, the image will get denoised at each completed pass.
EDIT: I forgot to mention that you can then turn it on and off via the layer interface, clicking on the eye for the corresponding entry.