Extremely poor core utilization only 15% of my cores T4.0

Started by Themodman101, August 06, 2017, 01:19:03 am

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August 06, 2017, 01:19:03 am Last Edit: August 06, 2017, 04:46:43 am by Themodman101
See attached image for the results im getting in my render tests. Only 15% CPU utilization.
The Terragen Version = 4.0

My Machine Specs:

E2695V3 Xeon CPU X2  (14 cores 28 threads each CPU) both together makes 56 Threads.
32GB of DDR4 2133mhz ECC memory
Windows 7 Pro (Fresh Install)

My settings are as follows:

micropoly detail = 0.5
AA = 4
Defer Atmo/Cloud = ON
Min threads = 1
Max threads = 64
Max Bucket Size = 256x256 with Autosize turned on
Sub-Div Cache size = 9000MB

The camera is facing the sun, with easy cloud Cumulus cloud layer at Quality 1.

I built two of these machines for the purpose of rapid rendering of CG, I was wondering if I have something setup wrong. The usage peaks around 19% sometimes. Even the cores that are being used arent being used effectively. I read in a number of threads on here (Albeit very old ones) that turning off hyperthreading can help. But it doesn't appear to in my case.

Thanks in advance for any advice!


after updating to 4.1 its improved some, so it appears that its the clouds! I get 100% pegged in task manager without the clouds. So is that all this is? Or is there more to the story?


My system seems to use the cores/threads as expected.  I did a quick easy cloud render test (tg4.1.11) with number of cores set to 8 and threads to 12 and I get a 76% cpu load (12/16). Then cores to 16 and threads 64 and I get 100% load.
(29Oct20) Ryzen 1800x, 970 EVO 1TB M.2 SSD, Corsair Vengeance 64GB DDR4 3200 Mem,  EVGA GeForce GTX 1080 Ti FTW3 Graphics 457.09 (29Oct20), Win 10 Pro x64, Terragen Pro 4.5.43 Frontier, BenchMark 0:10:02


Very strange. Could you post the .tgd you're testing with?

Do you happen to have a Quadro card in there alongside the 980GTX, or perhaps using the Quadro drivers somehow?

- Oshyan


August 06, 2017, 11:17:21 pm #3 Last Edit: August 06, 2017, 11:44:50 pm by Themodman101
Yeah see the attached file. And to answer you Quadro question, no I dont have a Quadro or Quadro drivers.

So I reinstalled 4.1 , loaded the terragen file, saved out a new version then re-rendered that new version. And it appears to be pegged at 100% now. Wonder if maybe something was wrong with my installation.

I attached the new performance image(With HyperThreading turned off)

So Ive seen a ton of different oppinions on the forums with regards to having HT on or off. With my machines specifically do you think I should leave it off since I have so many threads? Oshyan I believe I read 3 years ago you recommended leaving it off for anything higher than 16 cores. Is that still the case?


August 07, 2017, 12:51:28 am #4 Last Edit: August 07, 2017, 02:37:15 am by Themodman101
Now I have a new issue where Terragen 4.1.11 appears to be crashing my display driver when it completes rendering.it doesn't crash when i dont have the clouds in the scene. Albeit this is a very simple untouched scene other than the clouds, so I am testing other scenes right now.

That, is a new one for me haha. See attached my Dxdiag in case that information is useful.


Hey so every other scene appears to render just fine, its just that one scene. That I attached in my previous post. I received it from a buddy of mine who wanted to compare his render speed to mine. :P

So all appears well right now, let me know though if that file helps at all?


I rendererd your file 3 times after restarting my pc everytime in between.
No crashes. Renders fine with high cpu utilization. Took about 54 minutes on average (see specs in footnote).
NVidia driver is 384.94_desktop_win8_win7_x64_int_whql for my GTX 780.
Cheers, Klaus
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate


I'm glad you seem to have mostly got things resolved, especially regarding CPU usage. We no longer recommended disabling hyperthreading as subsequent improves to the render engine have made multithreading more efficient overall. You can still have decent gains upwards of 32 threads at this point (though with diminishing returns, which is true of most render engines).

We will test the file on our end to see if it crashes, but do make sure you have the latest graphics driver update as well. Klaus, thanks for testing too, that's helpful. :)

- Oshyan


Okay thanks Oshyan, and KlausK. Im still getting display driver crashes randomly when rendering through my many tests. But I doubt it has anything to do with Terragen. This machine is brand new and I probably need to make some adjustments to the setup.

I have updated to latest GPU driver for the 980, still crashes once in a while. I may need to modify my RAM slot to put it in the PCIE slot for CPU1. we'll see if that makes a difference. I will also re-enable hyperthreading as well.


Sounds good. Let us know if you are able to find the source of the crashes. Terragen does not make heavy use of the GPU, but the regular 3D Preview (not RTP) and parts of the UI use basic OpenGL functions. These should never cause crashes but do occasionally for certain people. Usually the driver version is the cause. Using the latest sometimes fixes it but not always.

- Oshyan