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ANSYS 17 (CFX Solver) Is Very Slow

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Old   March 19, 2016, 20:49
Default ANSYS 17 (CFX Solver) Is Very Slow
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Tazo Jorbenadze
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Hello Everybody,

This is my first post on this forum.

Do you use ANSYS 17?

Reason asking this is that CFX solver in ANSYS 17 is unbelievably very slow.

When I'm saying "slow" means that even a very simple steady state task with couple hundred thousands mesh takes long (something an hour or so while same task on previous versions was taking something 10 minutes or so). Although, ANSYS claims in all promotional videos claims 10x. Of course I'm not expecting it to run 10 times faster, but it does not even runs the speed what, for example, v16 was (or earlier versions) running.

Does anyone experiencing the same problem?

It's a same computer, same windows, same HDD, everything is same including myself. I'm using ANSYS for years and never experienced something like this.

What's wrong?

Thanks

P.S. By the way meshing is relatively fast compared to previous versions.
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Old   March 20, 2016, 19:48
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Glenn Horrocks
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Check your virus checker is not crippling it. Also check you have enough memory, other users are hogging CPU time.
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Old   March 20, 2016, 22:09
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Quote:
Originally Posted by ghorrocks View Post
Check your virus checker is not crippling it. Also check you have enough memory, other users are hogging CPU time.
Thank you for reply.

Tell me, please, what exactly to check with antivirus/firewall. I think I'm using something from Microsoft (forgot the name).

With memory no problem (if you mean amount of RAM).

Also, what exactly do you mean under "...other users are hogging CPU time..."?

Thanks
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Old   March 21, 2016, 18:01
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When a task is running turn on the task manager (windows) or top (linux) and see what tasks are taking up CPU time and hard drive time. If the antivirus is causing a problem it should should be hogging the CPU or HD.

If the firewall is a problem then it will probably completely stop the simulation (not just slow it down). It will mean the solver cannot get a license, cannot access an executable or cannot access a remote compute node and that will just stop the simulation.
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Old   March 21, 2016, 18:53
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If you already ran the case with the same settings on two different versions using the same machine (w/o other programs running), you could post the timing diagnostics at the end of the output file so others can see where the extra time is being used. Hopefully it is something obvious.

In addition, I am sure ANSYS CFX support personnel would like to have a look at your case.
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Old   March 30, 2016, 16:34
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Someone at my workplace reported that Version 17 was "really slow" as well. I have not checked it out myself yet though.
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Old   April 9, 2016, 09:46
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Quote:
Originally Posted by evcelica View Post
Someone at my workplace reported that Version 17 was "really slow" as well. I have not checked it out myself yet though.
Thank you Evcelica for reply.

Did you have any chance to look into details?

Whatever I do nothing helps.
May be there is something, somewhere, deep in the options/preferences/I don't know where... needs some check mark to be activated or removed...

I'm already sick with all these...
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Old   April 15, 2016, 17:26
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I just installed 17 and ran an old CFX benchmark:
17.0 is the same speed as 16.1 according to my benchmark: (1% faster actually)
I was running 5 distributed nodes with 1 core each.

I have no clue what your problem could be?? It's a long shot, but:
Have you uninstalled and reinstalled ANSYS?
Are you using workbench, or CFX standalone? I use standalone.
Are you participating in the Product Improvement Program?
I didn't, but supposedly there was an issue with this that has been corrected by the service pack 2 update:


17.0 SP2:
This service pack has corrected an issue related to outgoing data for the ANSYS
Product Improvement Program (APIP).


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Old   April 20, 2016, 05:59
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Quote:
Originally Posted by evcelica View Post
I just installed 17 and ran an old CFX benchmark:
17.0 is the same speed as 16.1 according to my benchmark: (1% faster actually)
I was running 5 distributed nodes with 1 core each.

I have no clue what your problem could be?? It's a long shot, but:
Have you uninstalled and reinstalled ANSYS?
Are you using workbench, or CFX standalone? I use standalone.
Are you participating in the Product Improvement Program?
I didn't, but supposedly there was an issue with this that has been corrected by the service pack 2 update:


17.0 SP2:
This service pack has corrected an issue related to outgoing data for the ANSYS
Product Improvement Program (APIP).


Thank you Evcelica for taking time for the test.

Hmm, Something really very strange indeed.

I was busy with some other stuff and got some time about 2 -3 days ago and just out of curiosity took one of the old tests for contra-rotating props (I have done that in v16 earlier) since it involves quite an aerodynamics in there.

So, the strange thing is that it did this test nearly in the same time as v16 done in those days back. Meaning is - it started working with the speed close to v16. Meshing was faster than in v16 (just re-meshed it with exactly the same settings as before from the beginning just to compare).

Pure Magic!

The only difference between the time I opened this thread and now is Windows - about a week ago (or so) it made something about 30 updates to itself.

Bad news is that now FLUENT (after all those updates) does not want to start. . Honestly, I don't care too much with FLUENT behavior but, seems to me, that "Houston has a problem" in ANSYS with this 10x "innovations".

I don't know what to think.
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Old   August 11, 2016, 17:21
Angry ANSYS 17.0 Solver runs very slow
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Ahmed Mirghani
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Hi everyone

I have the same problem with ANSYS 17.0 release. am working with ANSYS Workbench 17.0 "Static Structural" downloaded it a week ago. for the same problem, same meshing and same analysis settings, the run time takes more than 1 hr for 17.0 release whereas in case of version 16.0 it takes about 15-20 mints most. what is happening and what about the 10x thing they are talking about. am considering returning to workbench 16.0.

Any suggestions will be highly appreciated
Thanks in advance.
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