Persistent crashes in Arnold, even in simple scenes, saving threads still causing CPU spikes ~95%

[tomamoreton_xyz]

Hello, apologies as I am sure there are multiple posts like this, however I am seriously struggling to get to the bottom of near constant Arnold crashes, every render I do I can expect multiple crashes, even in basic scenes of a~3 lights and a couple objects, I really want to be able to run a render overnight without it crashing! 

My system: AMD Ryzen 9 5950X, RTX 1660 Super OC Ventus, 128GB Ram, running Maya 2025 and the most recent Arnold.

Currently I am doing everything I can find to minimise crashing: Optimising Scene size, setting project, keeping all files local (not on onedrive), flushing all Arnold cache's, deleting unused nodes, using TX files, Texture cache set to 8192mb, tiled and half precision exr files, max subdivisions set to 3,  the attached log files have higher samples but even when using AA~3 with adaptive sampling ~5 I am experiencing crashes.

The only thing I have noticed is that even when saving threads (saving 10, using 22) my CPU usage still spikes up to ~95% at points which I presume is when the crashing is occurring, it then lowers to where I would expect if I was saving this many threads, is this normal behaviour?  

I have attached a screenshot of this behaviour as well as a Log from a crashed file and a non crashed Log file, I am not too well versed in understanding the log files so maybe they are saying something I am missing?

Thanks for the help! It is very appreciated, let me know if you need anymore information.

[thiago.ize]

Thanks for the logs. They show that you are running Arnold core 7.4.2.2, which is not the latest. Download the latest mtoa (maya to arnold), which is currently 5.5.4.1.

01:57:51 18042MB | Arnold 7.4.2.2 [8ce34be5] windows x86_64 clang-15.0.7 oiio-2.6.3 osl-1.13.3 vdb-11.0.0 adlsdk-9.8.2.57 clmhub-3.1.1.43 rlm-17.0.1 optix-8.0.0 2025/06/27 09:06:14

The log shows that the crash occurs because you ran out of memory. Specifically, Arnold (really, maya and everything running in it since Arnold started) is consuming 20GB, but system wide you already have about 230GB of memory being used, which is the max your system supports

06:57:10 20810MB WARNING | can't allocate 524320 bytes (virtual memory : 230124 Mb)

You can work around that by increasing your Windows virtual memory size. But that's a band-aid. The real solution, if upgrading Arnold didn't help, would be to figure out what is using up so much memory on your system. Take a look at the memory usage in task manager after you've been rendering for a few hours. Any processes consuming lots of memory? Is it Maya (which contains Arnold) that is consuming all your memory or something else?

[tomamoreton_xyz]

Hi there! Thank you for the reply! So since those logs I have updated my Arnold with no such luck, I have always had this problem really with every Arnold update. Intresting what you say about virtual RAM, I have just had a look and I had another 86gb allocated (which seems like lots), on the reccomendation of other forums I have set it so windows manages it now, it was already on a custom value - probably from previous tinkerings! R.e what might be eating up my Ram i really dont know! Looking at performance manager when I render only ever shows about a third being used, ~ 40/124gb and from what I have noticed this doesnt go up as the render progresses either so there should be plenty availiable? Curious to know what you think! I can get another crash log now that arnold has updated if that would be helpful? Thanks again for you help. Best, Tom 

[thiago.ize]

I took a look at the Arnold code and the "(virtual memory : 230124 Mb)" printed out is how much virtual memory was allocated in the arnold/maya process, not system wide. That means this crash is very likely a bug in Arnold, maya, or some other plugin in maya. In case you're curious, this type of memory was requested from Windows but it might not yet be actually filled with data. We know it's not filled with data because the working set memory was only 20GB when the crash occurred and the big memory usage graph you saw in task manager stayed low. I believe you'll see the big memory usage in the task manager if you go into the details tab, and enable the "working set" (should be low) and "commit size" (should be high) columns or in the memory tab you look not at the "committed" numbers.

You said you can reproduce it with a simple scene? Can you upload here a very simple scene and instructions on how to run it to generate the crash? Hopefully it'll have no textures so it's a small zip file to upload. If we can reproduce it on our end we'll have a much better shot at fixing it.

[tomamoreton_xyz]

Thanks again, the plot thickens. Thank you for that information I did not know that! So I have attached a screen shot of the working size and commit size whilst rendering (its only been rendering half an hour or so) and the numbers are all fairly similar - could be relevant?  I will keep watching the values as the render progresses! I cant consistantly reproduce a crash, it seems almost completely random, sometimes occuring after an hour, sometimes (rarely) completeing without a crash.  I can tell you that with the file I have uploaded (the one I have been working on) which is quite simple: 3 objects, 4 lights or so and only 75 frames it has crashed maybe 3 times in the last 24h? Here is the file with all of the textures too, apologies theyre large textures, is this okay? I can upload without the textures or downsize them if that is better? https://we.tl/t-yBPyiY3nl6 is the Wetransfer link for the files! Thank you! Best, Tom 

[tomamoreton_xyz]

So I reset my prefs (classic) and then a pop up came up talking about an unidentified pop up saved in an unusual location, in light of what you said r.e corrupted plugins I deleted it and stability has improved! I still experienced a crash after about maybe 9 hours but that is a significant improvement. Normally when it crashes it clears straight to desktop however this ime it  came up with the 'autodesk has crashed window' with options to subit feedback etc.. I clicked for more crash information and it returned with this folder https://we.tl/t-zDWZPE7MJA (it wouldnt let me upload .analytic files to the forum) - although I personally cant make any sense of it - annoyingly I didnt have my logs on but I will render the scene again and I expect it will crash and I will get a log to see if anything has changed 🙂 Thanks for the help. 

[tomamoreton_xyz]

Here was another crash log from earlier, still only crashed once which is good going 

[thiago.ize]

Thanks for the scene. There is a memory leak when using "Output Denoising AOVs". Unchecking that (you only need that if using noice) in the Render Settings AOVs tab fixes the memory leak and also speeds it up a bit. I created MTOA-2554 for us to fix it.

[tomamoreton_xyz]

Intresting! Thank you so much! If I put in the AOV's required for Noice individually rather than the check box will this solve the problem and mean I can still use noice? its often part of my workflow, but I can prioritise higher samples too if crashes are going to be less frequent. Thanks!

[thiago.ize]

I haven't tried it, but I think that is possible yes. Give it a try and see if memory keeps growing with every frame. If you still have issues with that, you can also use OIDN to denoise.

[tomamoreton_xyz]

Great I ill do some testing! Although ODIN is not for sequences? Thanks for you help, Ill post my findings if anyone comes across this 🙂 

[thiago.ize]

Plenty of customers use OIDN for sequences. OIDN even won an academy award for its use in film. It should work fine as long as the input is not overly noisy. Try it and see for yourself.