I read that there is an issue with the RTX 4090 and V-Ray. Is this true? Other render engines are using 100%, but V-Ray is using 70%
So i dont think ive ever had consistant results of gpu usage, with my 3090 its fluctuates and there doesnt seem to be any consistancy so trying to figure out what is going on is a problem. I literally just videoed rendering in cuda, rtx, progressive, bucket..all were fluctuating. Went back to the same scene and it was hitting near 100 again. Now the scene isnt going above 80%. Something aint right.
There are a lot of issues with Vray GPU.
Vray always uses 2x as much Vram on my 4090 than on my 3090. And it’s about 1.5x as fast on the 4090 than the 3090.
The VFB keeps crashing to the point of rendering the program unusable at times - at least in Linux. This usually happens when displays are re-arranged in a multi display config. It’s like it tries to place itself in a previous position which it can’t and boom. And resetting the position will also cause a crash.This will then require the creation of a new render ROP in Houdini to get it stable again.
When my display isn’t connected to gpu0 (the one in the 1st PCIe slot) and to gpu1 (3rd PCIe slot) instead Vray GPU won’t render at all.
Textures won’t be rendered on GPU when motion blur is switched on, but only sometimes - like on Tuesdays because yesterday was Monday and everything was fine.
Why does it have to re-load the same assets for each frame in a sequence? A waste of time and resources and very annoying with larger textures.
If it does work it’s super fast esp with refractions, but sadly the time spent to find hacks around all the issues completely ruin that advantage.
Sorry about the rant but there are other GPU renderers out there that haven’t had issues like this for years.
That isn’t good news. I just dropped $1700 on a 4090 to replace my 3090. Is Chaos aware of these things and are they working on it. I mean, hasn’t the 4090 been out for a year now? Are you using the recommended driver?
The issues that I’m having aren’t 4090 specific. They happen on the 3090 as well.
Okay, so I am not alone.
Whenever I search for a solution to an issue I often find a thread that’s 1 or 2 years old with a mention that the problem is near the top of the priority list.
I have the latest version of both Vray and driver.
It most be a long list :). Have you tried Vantage?
No. I normally use Redshift, but I’m currently working on a project for a client who uses Vray.
I think this needs sorted ASAP. We’ve all be users along time. Some jumped ship and some stayed. Vray benchmark even runs at 100% yet the render software doesnt. Its rubbish.Taking an old scene with GPU lightcache is so problematic (infinite loop) an issue from many years ago. Change to brute force and you can get it working,although i did notice some textures look like the colours have been crushed (unsure why). Moving around in IPR is so delayed its like it has to reload everything with every camera move.
I tried in Houdini with Karma render engine and its fly’s 98%, rotate round, instantly updates and renders clean in like 2 secs.
I bought the card for my main business arch viz with vray and am very dissapointed. Enmesh doesnt even work. Check old posts and states a year ago its in top priority list
Just feels like tools have been added to wow but really they should be alot more stable.
IPR in vray has always crashed IMPO with itoosoft, Corona much more stable
I just hope they can sort it out as other render engines seem to of done
Everytime I try GPU it is more trouble than it is worth. I have spent the whole moring trying to render a scene, but everytime I stop the render, MAX’s viewport freezes and I have to kill MAX.
I’m glad i got the 4090 though, i just feel that it’ll be used for other projects using different software for now. I tested an old interior and it literally hangs and is so noisy when it eventually started working. I gave up in the end.
We’ll have to see what reply if any we get from Chaos.
Hi, thanks for the feedback. Please try to back your negative experiences about V-Ray GPU with examples and details about your workflow. I see some of you have opened separate threads with a bit more details and commenting only one issue at a time. I ask everyone to do that. Please open threads or tickets with your issues, include as much information as you can, scenes, screengrabs, log files, video recordings of your issues and everything will be addressed and fixed. We rely on your help and input to improve but please be constructive about it.
@glorybound make sure you are not leaving the “low priority” checkbox enabled when observing the low utilisation that you are talking about.
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Hello,
This is how the usage looks in my testing, there is no difference between a 3090 and 4090 in GPU usage..
First scene on RTX 3090.. Look at GPU1 usage graph, hovering 100% all the way
First Scene on RTX 4090.. Look at GPU3 usage graph, also hovering 100% all the way
Second scene on RTX 3090 hovering 100% all the way
Second scene on RTX 4090 a little lower than 100% because of how fast the 4090 is, still normal and expected behavior
I also tested variety of other production scenes in the same way, there is no usage issues specific to the RTX 4090 or RTX 4080 in V-Ray GPU
I tested on the same machine which has 3x 4090s + 1x 3090, I also tested on different machines with a single GPU, RTX 4080 and RTX 3090 the results are the same
Should you expect 100% usage graph on all scenes in V-Ray GPU?
No, there are multiple factors that could reduce GPU usage
- If you have many render elements in your scene, your GPU usage will fluctuate. It will look something like this,
In this case I have +25 render elements in the scene. If you have a few render elements in your, it is normal and expected to have GPU usage and GPU power draw fluctuate. - Another scenario that could reduce your GPU usage, is if you don’t have good enough CPU to feed your GPU. Specially for high-end cards like RTX 3090 and RTX 4090, you need at least 6 physical cores per GPU device
- If you have empty space in your rendered frame, like if you have big part of the render as backplate or HDRI or if it all black(empty) this will affect GPU usage
- If you are very close to the VRAM ceiling, you will see a message like Num Samples per thread reduced to xxx mbs, in this case you need to optimize your memory usage
- If you have low thread priroity setting on
- During GPU LC phase, which is handful of seconds usually at the start of the render.. the GPU usage will be 40 to 80%
- During kernel compilation GPU usage will be near zero, it happens only once after you update your driver, or V-Ray version
- Other scenarios for thermal throttling for the CPU or the GPU
What can you do to have the best CPU usage possible?
- Stick to progressive mode, and use the least amount of render elements whenever possible
- It is quite necessary to have a good CPU with at least 6 physical cores for a high-end GPU
- Avoiding empty space in the rendered frame whenever possible
Are other render engines using the GPU at 100% all the time?
No..GPU usage will fluctuate in the same way, and it will be lower on using Render elements or having empty space in the frame
For the people with 4090s, here is a test scene please let me know if you are getting different results to what I have
Best,
Muhammed
Are we any closer to improved responsiveness using GPU IPR?
That isn’t good news at all. A $500 card between a $1800 card and there is no difference in render times?
He meant in GPU % usage, not rendertimes.
GPU usage not render time, here are some render times for the RTX engine. Render time in seconds
Comparing the RTX 3080 to the RTX 4080 shows at least 1.8X improvement in render times. And Going from the 3090 to 4090 shows at least 2x improvement in render times
I tested the GPUs not connected to monitors, and all tests are run for at least 5 minutes(including scene compilation)
If you are getting less than 2X speed up with your 4090 compared to 3090, this is not expected to happen and you should start a ticket.
If you render time is 20 seconds, you will not get accurate results because scene compilation is taking longer than the actual rendering.
Best,
Muhammed
Okay, that is better news. If they can figure out the usage, then it is all the better. I am good with 2X the speed 
I have checked 6 scenes today, on 2 of the machines at office. The memory usage is very close between the RTX 4090 and 3090 see the attachments below(the 3090 probably has more VRAM because it is connected to my monitors)
Do you have multiple Houdini instances open? If you monitor your VRAM usage does V-Ray flush V-Ray after you close your scene? sounds like a memory leak
Please start a support ticket, and mention the name of this topic in the title. We cannot reproduce this behavior on our side, so we will need to take a look at your setup via remote access if possible
This is not normal, you should get at least 2x faster renders with 4090. Otherwise, something is slowing down your scene and we need to take a look at your setup
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Sorry to hear you are having trouble with the frame buffer. The Houdini team chased this instability for a while around the time we released version 5.1 and we followed along with the users who reported this. To my knowledge there is currently no issues logged regarding the frame buffer positioning. Have you gotten in contact with us about this issue in the past?
We will need more information on this.
I cannot find anything about this in our system either, we need to reproduce on our side to be able to investigate. We have multiple machines with 4x GPU and 6x GPUs to try and reproduce
Have you tried to render with other engines in this case?
Please send us a ticket, if we reproduce on our end I will make sure it gets addressed, that is if it an issue with V-Ray GPU
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We deployed multiple fixes for this, it seems that there are still some cases where the issue happens like what you wrote in the other thread.
Please share a scene with us, If we reproduce on our side I will make sure it gets fixed
This is on us, it is not an easy fix and requires research. We put effort into this in the past, and we will get back to this. It is still one of the most pressing requests
We are pushing on GPU Caustics now, once it is out we will get back to the topic of keeping resources between animation frames
Best,
Muhammed
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