Task Manager Multi-GPU Performance

[lunarstudio]

Hi. I'm not sure if this is normal (working as expected) but I was watching the Task Manager GPU percentages under Task Manager\Performance tab and it shows my standalone GPU (labeled GPU 2) in my screenshot at 0% constantly under the 3D tab when rendering.
However, the onboard memory does show as being utilized.

1. The OS is latest Win 10 with Fall Creators Update.
2. Card #1: nVidia Geforce GTX Titan Z (GPU 0 and GPU 1.)
3. Card #2: nVidia Geforce GTX Titan Black (GPU 2.)
4. OctaneRender 3.06.4 - 4.41. All devices enabled.
5. nVidia drivers: tried numerous drivers including the latest and they've all shown 0% on GPU #2. Currently I've reverted back to 385.69 due to numerous BSODs under the Windows Fall Creators Update.
6. I've played with nVidia Control Panel Multi-GPU settings including Maximize 3D Performance (currently shown in screenshot) which basically throws the Titan Z into a SLI mode. Disabling Multi-GPU mode causes the "Link" to be separated and GPU 1 will then show 0% performance as well.

[paride4331]

Hi lunarstudio,
could you kindly test using GPUz?
https://www.techpowerup.com/download/gpu-z/
then checking CUDA enable.
Octane works with SLI disabled.
Are you using octane subscription version? It limited 2 x GPUs
Regards
Paride

[lunarstudio]

I have three full licenses (Standalone, SU, and Max.)

I also went to try ORC a couple months ago and was accidentally subscribed to Standalone which was immediately cancelled. I hope that this isn’t impacting the GPUs being used.

Will try CPU-Z soon.

[paride4331]

Hi Lunarstudio,
Let me hear from you.
Regards
Paride

[lunarstudio]

I meant to get back to you but I'm in the process of repairing Windows 10 (fresh installation.)

Upgrading to the the MS Fall Creators Update has messed up many things including numerous BSODs when using multiple GPUs/Monitors.
nVidia Drivers past 385.69 are messing up many peoples computers so if you start seeing people mention crashes, suggest having them revert back.

[paride4331]

Hi lunarstudio,
try with 382.33, seems to be a very stable driver.
Regards
Paride

[lunarstudio]

Apologies again for the delay. I've spent over a week troubleshooting Windows including having to run a fresh install including the FCU and having to reinstall all of my apps again including disabling services, disabling other hardware drivers and testing various BIOS. FCU is a complete nightmare with many BSODs especially when the GPUs start processing.

I've determined there is major issue that many others have with Windows Fall Creators Update regarding multiple GPUs installed in one system. It doesn't matter which graphics card that you use as I've tested over three (a 1080, a Black, and Titan Z) with the same crashes. Using only one card does not result in a crash. Even my Titan Z (two GPUs on board) works fine as long as it's one slot.

As for NVidia drivers, it doesn't matter which ones you use as I've tested the most recent going back to early March of this year and they all crash when GPUs occupy multiple PCIE slots.

I've submitted a bug report to NVIDIA although it may not be their fault regarding these BSODs. I analyzed my dmp files/bug reporting and it seems related to NVIDIA's nvlddmkm.sys file.

This issue also happens with other GPU rendering plugins as well. It does happen on casual use as well, but not nearly as frequent.

I speculate (only guessing and can be completely wrong) that the major thing that changed with FCU was the way Windows 10 handles GPU memory with the latest DirectX 12 and how it relates to additional PCIE lanes being used.

So now that my computer is up and running again fresh with only one card (Titan Z), I'll try to give it another rendering test in a few days to see if the Task Manager Performance Panel recognizes the second GPU. I'll also take a look at GPU-Z. I should note that I've cancelled the ORC as I haven't used it just in case the accidental standalone subscription caused a lock down on my GPUs.

[lunarstudio]

UPDATE: You may want to tell customers to stay FAR AWAY from the Fall Creator's Update 1709 for Windows. It is extremely buggy, especially under heavy GPU loads.

I reverted back to 1703 with a clean install and prevented all Windows drivers from automatically being installed. Pulled my CMOS battery just in case. Now everything is working better than ever.
I've also added my additional cards back into the system and there hasn't been any crashes or stutters since then.

[paride4331]

Hi lunarstudio ,
I'm glad to know you solved this issue. automatic windows updates, It created issues to me in the past, using multiple graphics cards. My personal choice was going back Windows7. Windows 10 I am using a single Pascal graphics card and everything works properly with automatic updates too. Difficult to make a choise, certainly very frustrating waste time because of an automatic update. Anyway, thanks for sharing your experience, useful to know that.
Regards
Paride