max number of cpu cores

[alemanda]

Hi,
I recently updated my system to a dual xeon 14 cores. So Totally I have 28 cores.
When I launch a rendering I see that not all the 28 cores work together ... it seems that only 14 or 16 work.
Is there a limit in the number of cores used by Archicad?

[Anonymous]

Not sure about max number of cores used by ArchiCAD but if it is not using all the cores you could possibly run multiple sessions at the same time and break up the rendering into areas. Only thing I can see with the specs in your signature is that you don't realty have enough RAM to effectively use all cores, rule of thumb from reading many rendering forums is for at least 2Gb of free RAM after the OS has loaded per core.

Scott

[alemanda]

Thanks for your reply ...
after your reply I made a test.
Single instace of AC19.
I launched two renderings at the same time (actually the second one started few seconds the first one) ... and my machine uses all the cores
So It seems that there is a limit of cores per rendering ...

The "strange" thing is that I have 32GB of Ram. Running one rendering only the cpu usage is at 57% and it means that the machine uses 32 cores (considering HyperThreading I have 56 cores running). The question is: is there an optimal ratio of 1-GB per core?

[alemanda]

other test.
I downloaded a demo of Maxwell Render.
I launched the default render of a demo scene and it runs with all the 56 cores available ...
So I'm almost sure that there's a limit in cinerender ...

[Steve Jepson]

Don't confuse your CUDA cores (GPU) with the CPU cores. Maxwell will render with GPU, CineRender in ArchiCAD does not. You probably knew that. Just posting info for others. That card has 384 CUDA cores.

[alemanda]

Steve Maxwell uses CPU or GPU depending on your choice. I tested using CPU.
My video card is not the best for GPU computing I know ...

[Steve Jepson]

alemanda wrote:
Steve Maxwell uses CPU or GPU depending on your choice. I tested using CPU.
My video card is not the best for GPU computing I know ...

Do you get better results using GPU? Try one of the Maxwell bench mark models. And let us know which way is faster to reach the same level.

It would be useful to know hoe many CUDA cores it takes using GPU to make a difference in using CPU with plenty of memory.

What nvidia card is it going to take in order to be a better value than just getting a faster CPU and more memory? Also, I wonder what the effect a GPU card has on Studio and Fire previews ?

Also I am not so sure the GPU or CPU option in Maxwell is anything new. The nvidia cards have had settings for this a long time. You configure the card for use per the programs you use on your computer. You can do that in Maxwell now but I think you could already do that with the card settings menu ??

[alemanda]

Steve,
it seems that the engine works a bit differently using GPU or CPU. You get slightly different results. Some features are not available for GPU computing.
I tested my PC with the latest release of Maxwell (demo) and it is very fast. I just launched the Guggenheim museum scene as it is and in 5 minutes it reached 12 SL
Also the denoiser (new feature of Maxwell) makes a great job!

anyway I prefer using CINERENDER (mainly because the light objects are better coded for archicad) and I discontinued Maxwell subscription when I was at release 2.x

[Anonymous]

Cinerender generally uses the maximum number of physical cores available in a system. Therefore I don't think there is any limit set. website
I have to agree with sboydturner, that perhaps RAM is your limitation. I personally use a 12 core Xeon and I don't think I'll need an upgrade anytime soon. blog

[alemanda]

just an update about the above matter.
I'm performing some tests with AC21 and it seems that there is not the "limitation" I got with AC19.
Same PC configuration: AC21 uses all the logical cores (28x2=56) while AC19 uses only 32