Benchmark Test, Dual CPU, Low performance


I made some static and dynamic analyses of an embankment and a benchmark test eventually. The results are not satisfactory. I believe that there is a problem, but I cannot understand. I need some help. I prepared a pdf document explaining the case. Please find the document in the following link.

Thank you,
C Gulenc

We are aware that dual CPU machines do not use all of their computing power when running FLAC3D. This is discussed on the FAQ page under “Does Itasca software support multiple processors”:

Because of memory issues, we have shown consistent reduced multi-threading efficiency when running on a multi-CPU computer, regardless of the number of cores in each CPU. In this case, it is possible you will see increased overall efficiency from running two models in parallel on that hardware rather than in a series.

There is not much you can do about this, other than to run two FLAC3Ds on the same computer, as suggested.

As you have already seen, we recommend that all of the RAM slots are filled. Even if you are not using all of the RAM, we have seen computers run much slower when RAM slots are empty.

We have no idea how the user of DESKTOP-MG1F7L5 was able to speed up the performance. These benchmark tests are anonymous, so we have no way of knowing who this is. It is possible that when they ran the first test, they had some other process running that slowed down FLAC3D.

Thank you very much for the explanations. It is clear for me now.

Before filling the RAM slots, I attempted to run parallel computing for benchmark test. I tried to open two FLAC3D at the same time for several times but it froze the computer for the several attempts. Anyway, I was able to open after several trials. It gave following warning:

Then, I run benchmark test but it stopped the analysis and gave the following error:

And, task manager gave the memory error as it can be seen in the same figure above.

It seems that I cannot progress before filling the empty RAM slots, what do you say?

Thank you again,

Something weird has happened here. It looks like you are assigning all of the available memory to the 3DEC array. Assuming you are not actually using 3DEC, go to Tools - Options - Configuration, and set the main array size to something sensible (maybe 1000).

OK, I fixed it. Thank you. How can I run two FLAC3D model in parallel to employ dual CPU?
Is there any procedure or document to follow?

Well, you just start two FLAC3Ds on the same computer. You can limit the number of threads used by each instance (use the command PROGRAM THREAD n). So, for example. If you have a dual CPU machine with 80 threads, use the command PROGRAM THREAD 40 and each FLAC3D instance will only use half of the threads.

OK. I thought that there was a way to interconnect two instances when running in different FLAC3Ds. But now I see. I tried and I saw that two CPUs worked at the same time but there is almost no difference in terms of runtime performance. Thank you for your help.

I will share the results when we fill the empty RAM slots.

Kind Regards,

We filled the empty RAM slots, now 192GB (12x16GB) total, but the results are almost the same.

Kind Regards,