Why is there such high variation on the render rates of the same scene from one render attempt to the next?

[slitherhence]

I've noticed this across a dozen scenes now. Without making any changes I can render a scene one time and get 3000 iterations in 15 minutes... then close and re-open daz, load the scene again, and not get more than 150 iterations after 15 minutes. Close and reopen daz again, load the scene again, and get 1000 iterations in 15 minutes. Close and reopen daz again, load the scene again, and get 200 iterations in 15 minutes. It's extremely frustrating... especially since my current work flow is to create a dozen scenes and then batch render them while I'm AFK... only to come back and find out the 3rd render, 5th render, 8th render, and 11th render are unusable due to arbitrarily low iterations completed... but, upon restarting those renders with no changes to the scenes in question, they render much more quickly (after multiple attempts some times... but still).

There is no apparent relationship between the variance and other applications running on the system and I've checked repeatedly that nothing else is using more ram, cpu cycles, or gpu cycles than any other time.

This is with Daz Studio 4.15.0.2 64-bit, IRay rendering, Windows 10, RTX 3070 8gb, 16 gigs system ram.

I've been fixing computers professionally for two decades. I know what I'm doing regarding keeping a clean, smoothly operating system and diagnosing performance issues. As far as I can tell it's just Daz Studio being random... but I can't imagine many people would put up with an issue like this. Drivers maybe? Some archaic setting I don't know to check? I confuzed.

 

[rayminator]

daz have a cache called Dson cache files you can clear it but I don't know if that will help

 

[slitherhence]

daz have a cache called Dson cache files you can clear it but I don't know if that will help

It's worth a shot, thanks. I'll look into it when my current render finishes.

Honestly, at this point I would just transfer finished scenes to Blender and render there if the conversion itself didn't take 15 minutes.

 

[slitherhence]

Hmm, the DSON cache appears to have more to do with smart content than anything else... unless I'm missing something?

 

[Spin256]

I use ManFriday's Render Queue. It closes and reopens Daz for each render.

You must be registered to see the links

 

[Deleted member 1121028]

I can render a scene one time and get 3000 iterations in 15 minutes... then close and re-open daz, load the scene again, and not get more than 150 iterations after 15 minutes. Close and reopen daz again, load the scene again, and get 1000 iterations in 15 minutes. Close and reopen daz again, load the scene again, and get 200 iterations in 15 minutes.

Seems more like a hardware failure.
Variance between pixels completion is less than 0,0001%, not just Iray but any pathtracer.
There should be no 'randomness' once rendering kick in (can only happen before or after).

 

[slitherhence]

Just logged out to the sign in screen and back in, not even an actual reboot. Went from about 1 iteration every 10 seconds to about 1 iteration every second. Implies the issue isn't just a driver or OS issue.

Seems more like a hardware failure.
Variance between pixels completion is less than 0,0001%, not just Iray but any pathtracer.
There should be no 'randomness' once rendering kick in (can only happen before or after).

? I mean? If Daz had direct access to the bare-metal hardware that would be true. But real-mode applications haven't really been a thing on PC since the late 1990s. While the iray renderer may not introduce variability on it's own... it has to share the CPU, RAM, GPU, VRAM, PCIe Bus, and all the rest with dozens of other processes... and is beholden to whatever schedulers and resource allocation methods are employed by the OS and drivers. If any of those things are misbehaving it can cause quite a lot of variability in how long a given process takes to complete it's assigned tasks.

Maybe I'm misunderstanding what you mean?

I use ManFriday's Render Queue. It closes and reopens Daz for each render.

You must be registered to see the links

I'll definitely look into that. Even if it doesn't solve my issues I would prefer that approach anyway. Thanks.

 

[osanaiko]

Not sure if related to your issue, but rendering on CPU vs GPU would explain a 150 frames/15min vs 3000 frames/difference.

Daz's UI give's no clear indication that it is falling back to CPU unless you happen to see it scroll past in the details of the render progress window.

Use the Daz log (access via the daz help menu) to see for sure if the render fell back to CPU for some reason (normally it's because you are out of GPU vram).

Independent of that, the renderqueue suggested by Spin256 is a lifesaver.

 

[Deleted member 1121028]

? I mean? If Daz had direct access to the bare-metal hardware that would be true. But real-mode applications haven't really been a thing on PC since the late 1990s. While the iray renderer may not introduce variability on it's own... it has to share the CPU, RAM, GPU, VRAM, PCIe Bus, and all the rest with dozens of other processes... and is beholden to whatever schedulers and resource allocation methods are employed by the OS and drivers. If any of those things are misbehaving it can cause quite a lot of variability in how long a given process takes to complete it's assigned tasks.

Maybe I'm misunderstanding what you mean?

Same system regulary producing two different benchmarks for the same scene is not a Daz nor Iray problem, more a hardware one. That's what I mean.

 

[osanaiko]

Same system regulary producing two different benchmarks for the same scene is not a Daz nor Iray problem, more a hardware one. That's what I mean.

I don't rule out the possiblity of HW issue. it is a little hard to diagnose however.

I wanted to let the OP know that falling back to CPU due to lack of card VRAM is something that can happen if you've had Daz going for a while and your scene is on the edge of the available space - Daz is known to randomly leak some amount of allocated vram during iray renders/preview. Windows itself reserving some varying amount of space depending on what else is going on in the system (web browser with a webgl surface due to a video?) is also potentially an issue. These problems which cannot be direct controlled is is why one of the suggested possible solutions to cpu fallback is to restart daz and/or restart windows to get a clean slate.

 

[Deleted member 1121028]

I wanted to let the OP know that falling back to CPU due to lack of card VRAM is something that can happen if you've had Daz going for a while and your scene is on the edge of the available space - Daz is known to randomly leak some amount of allocated vram during iray renders/preview. Windows itself reserving some varying amount of space depending on what else is going on in the system (web browser with a webgl surface due to a video?) is also potentially an issue. These problems which cannot be direct controlled is is why one of the suggested possible solutions to cpu fallback is to restart daz and/or restart windows to get a clean slate.

I get what you mean, kinda discarded CPU fallback as it's wrote in plain letter in the status windows/log, and doesn't really stick imho with what OP wrote :

"Without making any changes I can render a scene one time and get 3000 iterations in 15 minutes... then close and re-open daz, load the scene again, and not get more than 150 iterations after 15 minutes. Close and reopen daz again, load the scene again, and get 1000 iterations in 15 minutes. Close and reopen daz again, load the scene again, and get 200 iterations in 15 minutes."

A memory leak may create a CPU fallback, that said a memory leak does not create variance in iterations/sec for the same scene (without CPU fallback indeed), opened in a few secondes/minutes intervales (ie: assuming system usage is the same).

 

[Deleted member 167032]

slitherhence How many renders do you batch at a time?

I get very similar as you with my 8gb GPU's. You have to shutdown your pc so the memory cache clears. Start up after a few seconds then start again. This only happens now and again. It seems some render even if its almost same scene you have setup just pushes past the 8gb memory GPU usage and fucks shit up. Restarting daz as Man Friday does will not help in my opinion as DAZ must either be stopped in Task Manager to let go of the Ram it holds on to or best shutdown the pc and start up. I know, ive had to battle with DAZ since 2017 using an old AMD 8 core with a 1060 3GB card.

Why it does this is still a mystery. DAZ is a bitch period. I am going to suggest to you to upgrade your system ram to 32gb if you can. YES i know its not so heavily dependant on system ram, but ive tested this on DAZ 10 when it came out. I upped from 24gb to jsut 28gb and I could render scenes i couldnt before.

Also try using the Nvidia studio drivers instead of the gaming version.

 

[slitherhence]

slitherhence How many renders do you batch at a time?

I get very similar as you with my 8gb GPU's. You have to shutdown your pc so the memory cache clears. Start up after a few seconds then start again. This only happens now and again. It seems some render even if its almost same scene you have setup just pushes past the 8gb memory GPU usage and fucks shit up. Restarting daz as Man Friday does will not help in my opinion as DAZ must either be stopped in Task Manager to let go of the Ram it holds on to or best shutdown the pc and start up. I know, ive had to battle with DAZ since 2017 using an old AMD 8 core with a 1060 3GB card.

Why it does this is still a mystery. DAZ is a bitch period. I am going to suggest to you to upgrade your system ram to 32gb if you can. YES i know its not so heavily dependant on system ram, but ive tested this on DAZ 10 when it came out. I upped from 24gb to jsut 28gb and I could render scenes i couldnt before.

Also try using the Nvidia studio drivers instead of the gaming version.

Anywhere from two to a dozen. Though the scene I create tend to red-line video memory consumption all on their own. So the CPU fallback concern osanaiko mentioned is something I watch out for. On that front I have CPU rendering completely disabled in rendering options. But I've noticed the post-processing can fall back to CPU even then... so i keep the daz log open in a program called bare-tail which updates as the log is writen... letting me see updates to the log as they happen. AS such, I can say falling back to CPU is not the problem here.

Same system regulary producing two different benchmarks for the same scene is not a Daz nor Iray problem, more a hardware one. That's what I mean.

I do usually treat highly variable computer problems (say a computer that locks up at random no matter what application is being used) as a sign that it's a hardware issue as software issues tend to have a much more limited scope. It just seemed like you were under the impression that other software on the system cannot play a part in the performance of Daz, which isn't the case. Like you seemed to be saying it has to be daz or hardware... it can't possibly be windows, drivers, or another application.

The reason I do not feel there is a high likelihood that it's a hardware issue is that closing daz or logging out and back in to Windows semi-consistently causes a large restoration of performance. Closing daz does not alter the hardware. Logging out and back in does not alter the hardware. But both are involved in freeing up resources that have been allocated by the OS to applications. This indicates a resource allocation and freeing issue... which is a software issue involving the operating system's management of hardware resources.

I could get into the nitty-gritty of how resource allocation works in windows (and other operating systems) but the short version is that daz could be losing track of the resources it is being given and keep asking for more from windows... eventually windows runs out of resources to give daz and daz is stuck trying to do its work with... for example... only 100 of the cores in the GPU... despite having been previously allocated 6000 of those cores. Then I close Daz and Windows frees all 6000 cores for use again. Reopen Daz, and now it has access to 6000 gpu cores again. That's an extremely simplified example and usually allocation of gpu/cpu resources is based on available cycles, not whole cores... but I think it illustrates the idea.

It could, in spite of all that, be a faulty graphics card. It just doesn't seem like a very likely culprit given the way render times can often be improved by simply closing and reopening applications. Also, if it is that... then I'm just fucking screwed. I cannot replace my graphics card at this time. And won't be able too, most likely, until I start making money with the game I'm working on.

 

[Deleted member 167032]

If my renders fall to CPU then it takes forever to finish and as you i have it deselected in my settings yet DAZ either jumps to that or crashes i believe. No you should be rendering without any issue honestly. I would still up your ram if i was you.
OR... reinstall Windows, i know it sux but this way youll see if its software or maybe hardware related then

 

[slitherhence]

If my renders fall to CPU then it takes forever to finish and as you i have it deselected in my settings yet DAZ either jumps to that or crashes i believe. No you should be rendering without any issue honestly. I would still up your ram if i was you.
OR... reinstall Windows, i know it sux but this way youll see if its software or maybe hardware related then

I'm probably due for a reinstall of windows anyway. :-/

 

[Deleted member 1121028]

I'm probably due for a reinstall of windows anyway. :-/

If it still persist over a clean install, may be wrong but wonder if it's not just your power supply dying rather than a faulty card . Kinda fit the scenario: no hard errors/memory allocation or cuda failure/artifacts, but huge drop out (as far as 95% decrease between high/low), ampere cards being quite power hungry in stress condition.

 

[Rich]

My first reaction would also have been "building up memory cruft, falling back to CPU rendering" but if you've eliminated that, have you verified that when it's rendering slowly that you haven't overheated your GPU? As I'm certain you're aware, GPUs will typically self-throttle when they get too hot. Wondering if the time spent closing, re-opening, reloading, restarting rendering might be giving it time to get out of thermal limiting. (Yes, I know, it's a stretch, and the kind of performance degradation you're seeing argues against this being the cause, but....)

 

[hardwire666]

If you're concerned about hardware problems, bench mark the hardware, and use HWinfo to monitor your temps and see if you're thermal throttling. If you're only seeing problems in Daz then I highly doubt your hardware is the issue. Also make sure Daz is updated. I know there were issues with the 30 series cards for a while after launch.

I'm always bouncing between Blender, Maya, and Daz and I hate Iray. Even with optimized settings and an optimized scene, Studio drivers and blah blah blah.... it's just a snail compared to what I'm used to seeing with other renderers. I run a 3950x, 32GB of RAM@3200mhz with an RTX2070. Iray is a just a slug and it really sucks when you know your hardware can do so much more. It's the whole reason I've been trying to figure out a good way to get scenes into Blender quickly and easily.

Really before you go and reinstall Windows and all that benchmark you're hardware. Daz is isn't the most well written thing and has it faults. Enough so I would point to it before a new GPU and so on.

Just my $.02 flame away.

 

[Deleted member 1121028]

Daz is isn't the most well written thing and has it faults. Enough so I would point to it before a new GPU and so on.

Daz has many faults, but not the one OP describe (or maybe he just broke a major flaw in the monte carlo method, who knows?).

 

[slitherhence]

So far aggressively restarting Daz has eliminated the high variance and seems to ensure better render times. I had thought I tested for this, but the last week's worth of renders have told a different story. I usually also log out and back in to get the best results when I start up a render queue... not sure how much difference that's making. Spin256's suggestion of using Manfriday's Render Queue has proven to be a big step up from the render queue script I was using before. Additional observations are that it happens most often when I use iray preview in the viewport or if I have iray renders that failed with errors. I'm also not sure if this played a part or not.

This really does strongly indicate it's a resource allocation issue and not hardware. And, as it only happens with Daz and not photoshop/blender/premier/etc... then it's a Daz issue. Daz has a memory leak of some sort. Really, with the number of other bugs I've seen it doesn't at all surprise me.

Daz has many faults, but not the one OP describe (or maybe he just broke a major flaw in the monte carlo method, who knows?).

Honestly, I don't think you understand what fault I'm describing. :-/