VRAM available for rendering with Windows 10 - #273017 (closed)
linvanchene
Posts: 1,382
Please be aware that this thread was created in October 2016
This thread was reactivated after almost a year by forum members.
This first post was edited several times to provide summaries and links to different sources.
- Request #273017 has been considered solved by DAZ3D staff based on the last provided information.
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Update 2018 10 02
Nvidia provided the following answer for MathWorks Matlab dated with 12 Sep 2018:
"NVIDIA have responded to confirm that this is expected behaviour. In summary:
WDDM2 releases 90% of available memory to CUDA.
A single application is only allowed to allocate 90% of that 90%, i.e. 81% of total memory.
NVIDIA are working with Microsoft to tighten this bound, and/or remove it on non-display cards."
Source:
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Update 2018 09 29
It is not clear if the limitation still applies in the same form when using Iray in DAZ Studio.
Different log files and 3rd party applications yield numbers that can be interpreted differently based on what information users trust.
The following questions had been submitted in Request #273017 on June 5, 2018:
"1) Based on what rules does Iray assign VRAM to the workspace?
2a) What does the log entry at startup of DAZ Studio 11 GiB total, 9.14774 GiB available actually indicate?
2b) Why is the entry not indicating 11 GiB total, 11 GiB available on GPU devices that have no display attached?
3) Can the DAZ 3D or Iray developers comment if the issue with Windows 10 and VRAM allocation made public by Otoy in 2015 still exists?"
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@ official information by Nvidia and Otoy staff
Official Otoy staff confirmed the issue with the following words in December 2015:
"A few people have noticed that on Windows 10 a large chunk of device memory is unavailable. This occurs even on GPUs which are not connected to a screen.
We can confirm this affects any CUDA application on any type of GPU. GPUs with more VRAM will have a larger amount of unusable memory. On 6GB cards, a bit over 1GB is unusable. CUDA applications effectively are not able to use this memory.
At the moment we don't know any workaround yet. If you often render scenes which use most VRAM on your cards, you may need to delay upgrading to Windows 10."
Source: https://render.otoy.com/forum/viewtopic.php?f=12&t=51992
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Nvidia provided the following feedback in June 2016 to Otoy:
"It appears that in Win 10, with the Windows Display Driver Model v2, processes will be assigned budgets for how much memory they can keep resident. What we are noticing is that WDDMv2 started to impose a limit on total process allocation size. This is briefly mentioned here:
https://msdn.microsoft.com/en-us/library/windows/hardware/dn932169(v=vs.85).aspx "
Source: https://render.otoy.com/forum/viewtopic.php?f=12&t=51992&start=20#p279386
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Windows 10 reserving / blocking VRAM , or Memory is unavailable means:
With a GPU that features 11 GB you can add geometry and textures up to 9 GB and then you will notice that you cannot anymore add more.
Before: On windows 7 systems the full amount of VRAM of cards with no display attached was available for rendering tasks.
My own test results:
On Windows 10 systems 1 GB of VRAM of 6 GB cards is not available for rendering tasks
On Windows 10 systems 1.4 GB of VRAM of 8 GB cards is not available for rendering tasks
On Windows 10 systems 2.0 GB of VRAM of 11 GB cards is not available for rendering tasks
Other users reported:
On Windows 10 systems ~ 2.4 GB of VRAM of 12 GB cards is not available for rendering tasks
It is to be expected that a GPU with a display attached requires some VRAM to be reserved for diverse tasks.
The core issue is that those values are also reserved on GPUs with no display attached!
The additional issue is that memory unavailable for rendering tasks seems to be increasing on cards with more VRAM.
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@ How can you verify those limitations yourselves?
update / edit - 2017-05-28:
Veryfiy with DAZ Studio Iray Log file:
garyh.pub found the information how much VRAM is actually available for rendering in the DAZ Studio Log File.
"Help -> Troubleshooting -> View Log File...
Search for "GiB available" in your text editor"
compare:
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Verify with Otoy OctaneRender
I added a quick guide to the "Technical Help" section that shows
- how to download and install the OctaneRender Demo
- Export a scene as .obj from DAZ Studio
- Import the scene in the OR Demo
- check how much VRAM is used by geometry, textures and how much VRAM is blocked on your system
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@ Threads about this limitation on the Microsoft forums
oguzbir started a thread on the official Microsoft forums:
He then was asked to create a new thread on the Technet forums:
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Updated 2017 11 13:
Additional information:
- GPUs in the task manager
Starting with the 2017 Windows Fall Creator's Update GPU information will be displayed in the task manager:
"To understand all the GPU performance data, its helpful to know how Windows uses a GPUs. This blog dives into these details and explains how the Task Manager's GPU performance data comes alive."
https://blogs.msdn.microsoft.com/directx/2017/07/21/gpus-in-the-task-manager/
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Comments
Mmm, I'm not sure whether this was for sure a Windows 10 thing, because this has occured back in Windows 7 as well. My experience with it is that the VRAM used is associated with storing the desktop, window content, and so forth...
The VRAM amount can be reduced by driving your monitor through your integrated graphics port.
I think what's being said is that even if the video card isn't being used to drive a display, Windows is at least showing that VRAM is being reserved on the card.
I don't think that's being said in either of the threads, nor has that been my experience. If it's off of a fresh boot, Windows shouldn't take up any VRAM if the card is not driving the display.
If it's not off a fresh boot -- ie. switching VGA plug -- then the VRAM amount should decrease as windows are closed. The window manager would of course persist on the PEG until a full reboot.
At any rate, it's recommended that a secondary PEG card or IGP be used to drive your monitor anyway, in order to prevent the card from drawing at the same time it's trying to process the render.
...so what about setting up one card just to run the display/desktop and another just for rendering? Is that even possible?
Ridiculous to progressively lose more VRAM just because of Windows. The net memory of the 6 GB card is 22% of the total while the net for a 12 GB Titan X it is 33% of the total. So it would mean an 8 GB 1070/1080 would lose about 28% of it's total memory allowing for only 5.76 GB useable for rendering.
This is not good as it makes high memory GPUs worth even less.
Maybe getting that server board which can support 4 CPUs, installing four 8 core Xeons,128 GB of memory, a low cost 4 GB GPU to handle two displays, spending 700$ for Windows 2008 Server Edition and just rendering in CPU mode might be more cost effective in the long run.
It's how my machine is set up, a Quadro K4000 for display handling and a 780ti set as the default render card, works fine though I have to becareful when I update drivers as the two cards don't share them.
I often have DAZ Studio on one screen rendering away while watching movies or playing a game on the other, erm I mean working on the other screen... honest!
I probably should have added more information in the first post about why this matters.
Basically what is being said is:
If you use any GPU render engine with windows 10 a percentage of the VRAM will not be available.
Those who are using OctaneRender had access to tools that clearly show the amount of VRAM
- used by the system and other applications
- used for geometry
- used for textures
With windows 7 and 8 a small percentage may also have been used but this was neglectable.
Now since 2015 the amount of VRAM that is reserved by windows 10 is significant.
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The main issue we are facing is that most regular users like gamers or normal video editors do not have any access to tools that monitor VRAM usage. So even if in theory a lot more people are affected by this change there is no public outrage because people just don't notice.
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In any case oguzbir was adviced to create another post on the dedicated microsoft tech forum:
https://social.technet.microsoft.com/Forums/en-US/15b9654e-5da7-45b7-93de-e8b63faef064/windows-10-does-not-let-cuda-applications-to-use-all-vram-on-especially-secondary-graphics-cards?forum=win10itprohardware
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Yes, the amount of people who are using GPU to render are only a small percentage of the windows 10 users. Nevertheless, there is still the possibility that there is a workable solution to adress this issue so it is worth making some efforts to finally get this issue noticed.
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Kyoto Kid, I use a GTX 470 for my display and render on a GTX 780ti.
Yes, that is precisely what I'm proposing. I use the IGP on my 4790k to drive my monitor while my 960 4GB renders the scene.
Aside from memory advantageous, it's also beneficial in that rendering and driving the monitor at the same time will cause Windows to lag significantly.
And I use a GT 740 for both my monitors, leaving the 980 ti free to just do rendering.
Update / Edit: Added example screenshot of a test scene
Based on the feedback to the linked threads a huge challenge on they way of resolving this is that most users have no way to tell how much VRAM is available in their applications.
Does anyone know some free tools, apps, benchmarks that clearly show:
- Maximum available VRAM installed on the graphics card
- VRAM currently available for use
- VRAM used
Example:
Total VRAM: 6144 MB
- available: 4542 MB
- used: 347 MB
GPU-Z should tell you
I know I use about 500 MB idle for my 3 monitors with Win7 for example
I have GPU-Z installed but on first quick glance only detected
- maximum installed VRAM (memory size)
But did not figure out where to look for
- VRAM currently available for use
- VRAM used
-> Can anyone explain on which tabs in GPU-Z that information can be found?
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I have an older version and is second tab on that, looks nothing like yours
am on my ipad so cannot look
The screenshot is of CPU Z which is different & doesn't have the information you need
You need this one: https://www.techpowerup.com/gpuz/
ah good catch tottallou
@OP
I use Windows 8.0 (yes eight point zero), and I've seen something similar, but it seems to be Daz that is reluctant to give up RAM, even after purging and using the script in Daz, some GPU RAM is still being maintained on the 980ti (second image - empty scene) Closing Daz resolves it though, and it reverts to zero; it can take a some seconds to happen on occasions.
Next time i try W10 on this comp, I'll see if the same happens. I don't remember it last time I used W10 though, although it was only for a few days, and can't recall if I did actually use W10 with Studio.
@Outrider42
The 970 does have 4 GB or RAM, and IRAY can use it all; before getting the 980ti, I used the 970 as a render card, and had scenes well over 3.5 Gig. The issue with the RAM was it was directly accessible, but only via components that would be busy accessing their own RAM. I can't remember the name of them, but AnAndTech has a good article if you want to look.
... And yeh, the backlash would be impressive.
D|S has continued to use 4GB or more of my 980Ti after closing!!!! I have had to kill it in processes in task manager so I could use Octane in Carrara. Its a real resource hog!!!! the same scene will use a fraction of the VRAM in OrDS that it does in iray.
I'm quite well versed on that situation. I used that example to demonstrate that something like this would be huge. Windows 10 already has some backlash, but gamers have mostly taken to it (it has quickly passed 7 on the Steam survey as the most popular OS, and I tend to think 140 million or so Steam users count for something.) And that is due in large part to DirectX 12 and other performance boosts 10 gives. So if 10 is holding back 20-35% of a gpu's vram from games, that would be a huge story. Everybody expects Windows to use some vram, but not that much.
I have a 980 ti and the only time I see the Vram stay in use is if I don't close the render window.
I now use my new nvidia 8 gb 1070 to run my monitors but originally I used a cheap nvidia 640 to run my monitors and that left my 780's for rendering. Another alternative is too run a ati and nvida together. Get a cheap ati to run your monitors if you motherboard does not have a integrated graphics card and that will freeup all the vram on your video card.
...I thought "a Quadro (which originally listed for over 800$) to run the display and GTX for rendering?" Both have the same VRAM (3GB) so first impression, I would have the Quadro as the main render card until I saw it had only 768 CUDA cores compared to the 780ti which has 2,880, better memory interface, and higher resolution capability.
Yeah I don't usually do anything else on my system when rendering. The process is slow enough the way it is rendering epic size scenes with just under 11 GB of available system memory.
I need to find some way to get the funds up to upgrade both my system's memory and the OS.
...just one more reason to stay with W7 or 8.1. I would be totally fumed If I shelled out over 2,000$ for a pair of water cooled Maxwell Titan Xs and only had the memory resources of a 1070/1080 at my disposal.
...3 GB? That would never work for my epic size scenes.
...I only have an old 1 GB 460 and I get white flickering sometimes when I load new content as well as "white outs" of the viewport while loading scenes.
Yeh, one would think it would have come to light if there was an issue... But I'm watching this space. :)
@ GPU-Z / CPU-Z
Thank you a lot for pointing me to the proper suggested tool.
I applogize for the confusion. I indeed mixed up CPU-Z (which I have been using for a while) and GPU-Z.
Unfortunately the same issue remains in GPU-Z:
It does not clearly indicate the currently available VRAM. It only shows how much VRAM is used.
People not involved with GPU rendering may not have any 3D models on their system that they could use to build huge scenes to try out how much it takes to "fill" the VRAM.
-> So we are still looking for another tool or app that would allow everyone to show how much VRAM is actually available on their system to work with.
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@ why are the gamers currently not yet aware of the issue?
The "standard" graphics quality settings for games are designed to fit on the amount of VRAM that the "average" user has available.
In the past the "Ultra high quality" graphics were set up to match the high end graphic cards specifications.
Each year those values may be adjusted by the studios based on the graphic card specifications available.
Nevertheless, if you check the latest pc game reviews you will notice that there are hardly any games that use more than 5GB VRAM.
-> If most high end gamers use cards with 6GB or even 8GB VRAM they simply have not run into any game that did not fit their VRAM.
This means for some reason the current generation games are not using the full potential of the available VRAM.
@ Nvidia is aware of the problem
Based on forum posts in June 2016 by official Otoy staff they had been in communication with Nvidia.
Here is what they had to say about it:
"It appears that in Win 10, with the Windows Display Driver Model v2, processes will be assigned budgets for how much memory they can keep resident. What we are noticing is that WDDMv2 started to impose a limit on total process allocation size. This is briefly mentioned here: https://msdn.microsoft.com/en-us/library/windows/hardware/dn932169(v=vs.85).aspx"
Source:
https://render.otoy.com/forum/viewtopic.php?f=12&t=51992&start=20#p279386
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So no, we are not making this problem up.
This issue has been acknowledged directly by Otoy staff and indirectly by Nvidia.
I can reproduce this issue with different test scenes on a constant basis.
OR test scene - 6144 MB VRAM card - 5052 MB available - Scene size 146MB
The reason why I try to raise awareness of this issue now is exactly because it is time to purchase new graphic cards.
If we spend large amounts of money for new cards we should also be able to actually use the full amount of VRAM installed.
Reading through all of this seems like this is a repeat of a very old issue/behavior. Back in the day, Windows did the same thing with system RAM, specifically when used with on board graphics.
I had wondered why I could render more/larger scenes on my Linux install of Studio than on the Windows one. Basically the same card in both machines...out of the gate, Windows is using almost 2x the card's memory before I hit 'Render'. Windows has and always will be a graphics memory hog...and if this is what it seems to be, even more so in Win10.
@linvanchene, How are you confirming that the scene size is 146.1MB?
OctaneRender standalone shows the numbers of the scene the "GPU quick information" to the right below the viewport:
Example:
In my last post there is a screenshot with a red arrow pointing at
1 tex, 2210 tri, 2 meshes, 3 GPU, 146,1 / 5022 / 6144
-> the 146,1 is the size of the scene in MB
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In the now outdated OctaneRender 2 manual the "GPU quick information" is shown
https://docs.otoy.com/Standalone_2_0/?page_id=138
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Now if you have some time to look at that screenshot on the linked manual page...
When OctaneRender 2 was released in June 2014 Windows 10 was not yet around.
So that old screenshot was probably made on Windows 8 or Windows 7.
the numbers there read: 122 / 5978 / 6144
VRAM on card 6144 MB
Scene size 122 MB
The available VRAM was still 5978 MB !
Now with windows 10 we only have around ~5000 MB of a 6144 MB card available for use.
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Let's do another test with a scene that features also some textures:
Test scene car:
Here is another view that shows how the scene size is added together:
For this test I used only 1 of the 2 rendering GPUs:
Scene size is around 440 MB
Engine run time data: 140.3 MB
Geometry: 106 MB
Image Textures: 182 MB
etc.
-> Unavailable Memory 1 GB !
The GPU used for rendering is not a display GPU. Why would there be any unavailable VRAM at all if the only other applications open are File Explorer and Internet Explorer?
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I tested this scene with all 3 GPU induvidually. The two rendering GPU used alone had 1 GB of unavailable VRAM.
The display GPU had 1.1 GB unavailable memory.
(Tested while File Explorer and Internet Explorer were open.)
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