Studio 4.20.0.17 iRay flakey, slow ... very slow

lamoid_5f20d3e469

Dear Folks,

So I finally upgraded DS from 4.16.0.3 to 4.20.0.17 (not a beta; the full release version). At the same time, updated the nvidia drivers to the latest studio version. (517.40). First thing I noticed was that, usually, iray would not render in the viewport. Sometimes it did, and when it did it would take mainutes to start rather than seconds as before. But, I could not predict when it would work or would not. Then my actual iray renders took at least twice as long as before. Ocassionally they would have taken at least 10 times as long, had I not stopped them when after a half hour and the rendering progress was at 2%. I was continually monitoring gpu usage and it was working every time. It was not falling back to the CPU. So I tried rollwing back the nvida driver to 512.15. That had no effect. Having used DS for nearly as long as it has existed, I learned to always backup the current dir ("C:\Program Files\DAZ 3D\DAZStudio4") or rename it in place before installing a new version. I went back to v4.16. Now the viewport iray works and the rendering speed went back to normal.

Have you had this problem?  Any ideas why it happened? or how it could happen. I imagine this was not the way it worked for everybody or I would have seen it on the forums. BTW, if there are other posts elsewhere in the forums that deal with this 4.20 issue, I could not find them. I am sure they are their but Daz's forum search function is so bad as to be nearly useless. I you know of a thread that might contain the answers to my questions, please let know.

Thank you!

PS: I was unable to install 4.20 using DIM. It would quit within seconds of starting the install and give no reason for its failure, so I installed the binary from https://www.daz3d.com/downloader/customer/files#prod_13176.

Seven193

What graphics card?  And how much GPU memory does it have?

lamoid_5f20d3e469

Thank you for your question, Seven193. It is an nvidia 2070 with 8GB DDR6 RAM. I am not sure why this would matter since the same device was trelatively fast in DS 4.16 but very slow in DS 4.20. Does 4.20 require more resources from the GPU than did 4.16? How might that result in a slow down? Based on the render progress window, the entire scene fit with room to spare in the GPU in both 4.16 and 4.20.

PerttiA

How do you monitor the VRAM usage? Running a 8GB RTX Card on W10, leaves about 4GB's available for geometry and textures.

Rendering taking twice as much time as before, is an indication of the process not having enough VRAM for the needed "working space" and render taking 10 times as long means the CPU is doing the rendering, due to the GPU running out of VRAM

Seven193

Best place to start troubleshooting is Help -> Troubleshooting -> View Log File.  Look for any errors or warnings about your CUDA device or drivers.

lamoid_5f20d3e469

Thank you PertiA and Seven193 for taking the time to comment and ask questions! Even when the render was on its way to taking at least 10 times as long the log file indicated that the GPU was doing the rendering. My process monitor also showed the GPU at 100%. The log files did not indicate that anything was wrong at all. Even at best, 4.20 was just half as fast as 4.16 is in rendering. I do not know why that was happening.  I've had other strange anomalies happen on my system before. For eaxmple, Man Friday's render queue stopped working for about 8 months, then started working again mysteriously. Also it used to be the case that the flag -allowremote let me start renders over remote desktop. But now that no longer works. I suspect that MS Windows 10 is the source of most of these problems. And of course becuse MS has no customer service whatsoever there's not a chance of finding out what problems WIndows 10 is bringing.

I am just curious to know if anyone else has had this experience with DS 4.16 abd DS 4.20.

alan bard newcomer

one quick question... if you watch the render box and have it open for verbose....
that window will be open as everything is loaded into the card etc. 
the actual render where the sampling is updated ... can be a lot shorter... than the total render 
which suggest something in the scene or just simply daz isn't tossing data to the render engine fast enough or the render pre-set is bogged down.
Last render I've been fighting with has some items that apparently take a long time to load into the gpu for rendering so that the total time is 2/3 set up and 1/3 writing the sampling