Question about how blender uses resources of my computer


I have a few questions about Blender that troubled me for some time and can’t easily find good answer to my questions on internet.
So here they are:
I’ve heard that you can use blender with cpu and gpu computing, how i do that? Because i downloaded beta version and no such things are possible. At least i did not succed (i will provide more details if necessary)
How are the gpu and cpu used when:
-Making a physics simulation
Why i ask these things? I watch in task manager when i give it a cloth simulation for example, and gpu is barely used like 12% from time to time, but around 35-40% cpu, why is that? I use “GPU compute” setting
Same for rendering, GPU is not used at 100% but CPU sees use. How can i overcome this difficulties?
Why Blender doesn’t use all my computer resources and yield me better render times and simulation times?
Lenovo laptop
i5 7300HQ
8Gb Ram
Gtx 1050 4gb
Windows 10 Enterprise

(sundialsvc4) #2

It’s really up to the operating system how much resources any program will be allowed to get. And, the external views presented by a task-monitor are only approximations. Other things can slow down a program, particularly I/O … specifically including the I/O caused by virtual memory paging. You’d need to use a so-called “profiler” to see exactly what factors are causing (Blender) to use less than the amount of resources that you intuitively expected.

(Casey) #3

OK, GPU compute is just for rendering scenes. When you’re working in the 3D viewport, and doing things like animations and cloth simulations, those are very CPU dependent. You don’t really get into GPU loads unless you’re trying to model while using a lot of lighting and textures and stuff, and you’re rendering those live with something like Eevee. But the act of calculating all the movement of your verts, and such is a CPU load. Showing the results of that on your monitor is a GPU load, but modeling in the viewport is not exactly graphics intensive, which is why you don’t see your GPU working very hard in that scenario.

As for rendering, I find the combination of GPU and CPU compute to be…less than ideal. GPU compute likes to work with larger frames, CPU wants tiny frames. However, you have to pick a size and so one half of your render is going to be so non-optimized it’s almost not worth it, in my experience anyway. I don’t think CPU compute is worth it for rendering at all, unless you run into VRAM limits and you have no other option. Even my Ryzen 7 2700x (8 core, 16 thread) cant compete in rendering against a single GTX 1070.


Thank you for the condensed yet informing answer.
In the future i’ll invest in a server for rendering, or maybe a better laptop but for now, this laptop does the job great.
Still have alot to learn.