What should I expect to be faster for stills? 36-Core Dual E5-2696 v3 Max 3.8GHz 128GB RAM or EVGA GeForce GTX 1080Ti 11GB
I ask because I ran RT, using the GPU and it was slower than rendering using progressive in the CPU. I also ran RT in hybrid mode and that was also slower, which didn’t make much sense.
Are you sure you are rendering for the same noise levels?
Best,
Blago.
I am just using the defaults, so I’ll have to check. It sounds like RT should be faster and RT with GPU/CPU should be fastest, correct?
Would definitely be interested in the results because that’s a massive price difference between the two 
The image sampler behaves differently in RT/Adv. The easiest way is to compare the renders after the same amount of time. Also, make sure to use V-Ray GPU as a production render, since it’s ray bundle size / rays per pixel / etc settings there are optimized for final frame rendering.
Best,
Blago.
I believe (correct me if I’m wrong) that GPU’s typical excel at calculating direct lighting. So your interior scenes which rely on indirect lighting (GI) would require more than a single GPU to match the performance of your CPU. Plus not having to think about memory constraints on your GPU vs CPU is something to consider.
This is not quite the case. This is more what like the results should look like.
Best,
Blago.
Okay, good to know, Thank you!
I’ll read earlier. Are there any setting I should tweak to improve GPU render times?
Ideally it should work out of the box.
Best,
Blago.
I’m curious how this ends up. I’ve got the some type of results but my machine isn’t pimped out like Bobby’s is. The CPU’s win every time in my tests, but every article I read tells me this is impossible. I’m doing something wrong but I don’t know what…
Hybrid has to be faster if it is using both the CPUs and the GPU’s. My current interior is using 19MB or RAM and I have a 11MB vcard, so I am assuming everything can’t fit on the card. Unless it’s not apple and apples when it comes to CPU and GPU RAM. Regardless, in hybrid mode shouldn’t it fill the vcard and rest renders on the RAM?
After reading the below article, there should be no reason why GPU+CPU wouldn’t be faster than anything else. In my case, it isn’t the case, so I am confused.
https://labs.chaosgroup.com/index.php/rendering-rd/understanding-v-ray-hybrid-rendering/
As I said, if you are not testing rendering for the same time + comparing noise after that (and the same settings, for example BF+BF), your test might not be accurate.
Best,
Blago.
I’ve run into an issue before where RT was rendering very slowly (in production mode). Usually, this goes away when stopping and restarting the render.
I think RT is still some kind of unicorn to most. People are buying GPU’s, thinking that they’ll whip through scenes like nobody’s business, however, I think it might be a misconception. Unless I am mistaken, we are still limited to one GPU, correct. I had one dedicated to my monitor and the second was for V-Ray. If your scene won’t fit into your single GPU RAM limits then it’s a moot point; it won’t flow over into a 2nd or 3ds card.
Also, you have to build your scene to be rendered on your GPU because many things are not supported. I tested hybrid rendering on an interior scene I am working on and I am getting Fresnel reflection errors and my highlights are blown-out. Now, if you could run a script to set your scene up for RT, that would be awesome.
Bobby, another good reason to use RT/GPU as the Production Renderer when Hybrid rendering is the default Brute Force/Light Cache usage. Much faster than BF/BF in active shade.
-Alan
Bobby, FYI, everyone I know (and that is a considerate amount of folks) who has bought GPUs for production rendering did it only after testing and proving their workflow with RT/GPU.
Just to let you know that there are plenty of work-horses to go with those unicorns…
-Alan
If I can chime in here - the last major project I did, I decided to go with RT all the way - and specifically bumped up my 2 x 1080 ti’s to 4 x 1080 ti’s just for this one project.
I found I needed to do a *lot* of tweaking of materials to finally get RT to render without crashing, but once I did get all those out of the way, the speed improvements were *definitely* breathtaking.
Not only that, but I love the visual interactivity RT and GPU rendering affords.
So, for this project I mention - my 4 x 1080ti’s were churning out renders in 6 minutes in RT (4 x GPUs).
Once the project was delivered and I had time to see how long CPU Adv rendering would have taken, I found my no-slouch 5960x would render that same scene, same noise thresholds etc in 26 minutes…
6mins vs 26 mins is what I found.
I reckon your Dual Xeon is about twice as fast as my 5960x (by memory as my work last year had those Xeons) - yet you only have ONE 1080 ti.
Answer… you need more 1080 ti’s my friend.
PS - I often read that RT doesn’t support this or that, but I have to say, that in my case, those unsupported features aren’t deal-breakers (I don’t need them anyway) - so for me RT is a very worthy render engine that is going to be my default go-to renderer as much as possible.
NOTE - RT is a different render engine, so you *will* get different results coming out of the box and those results may or may not be to your liking - for my clients, who loved what I did, I know they aren’t really interested in the details we can see (and they can’t or aren’t bothered with).
PPS - I also found that CPU & GPU wasn’t faster, but slower and I was told that my CPU isn’t a good match for the performance of my GPU’s - that doesn’t make sense to me, because from my simplistic point of view, I was of the belief that the “more hands to the pump” the better…