Mechanica not using up available system memory

DamianCastillo · ‎Aug 17, 2011

We are running Creo Elements/Pro 5 64-bit on Windows 7 Professional 64-bit.

For some reason, Mechanica is running very slow but it's not using the available system memory. It seems that Mechanica is using very little RAM and mainly using the Hard Disk while it's calculating.

We have 6GB of RAM and have 3.2GB available while Mechanica is running. Mechanica is making the entire system run slow and it seems that it's using lots of disk space to run.

How can we make Mechanica use up the available RAM?

"Too many people walk around like Clark Kent, because they don't realize they can Fly like Superman"

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Chris3 · ‎Aug 18, 2011

Analysis -> Mechanica Analysis -> Run -> Settings

Change the Memory Allocation to whatever you want. Its been my
experience that while this helps, Mechanica is still going to write a
lot of data to the hard drive. Depending on the complexity of the model
and what type of analysis you are running, the files can easily get to
be several Gb. These files need to be written to the hard drive so the
analysis can be viewed after its done running.

Chris

PAULKORENKIEWIC · ‎Aug 18, 2011

Some guidelines from the PTC Help files:

Memory Allocation
Select Memory Allocation to turn on RAM allocation. This setting is turned off by
default. The value you enter sets the amount of RAM reserved for solving equations
and for storing element data created by the iterative solver. The engine dynamically
allocates the rest of the memory it needs for the run.

Before you run design studies, you can set the amount of RAM the engine uses.
Depending on the amount of RAM installed in your machine, you might be able to
improve the engine solver performance by changing this setting.
When you select Memory Allocation, Mechanica displays the default value of 128
megabytes. You can change this default value by setting the config.pro value for
sim_solver_memory_allocation to a different number. The value you enter must be
greater than 0.1.
Some tips for setting this value include:
* You can use the default allocation for any run.
* If you have a lot of RAM on your machine, you may want to enter a higher RAM
allocation number so that large models will run faster-you can slow the run
substantially if you specify an allocation that is too large to fit in available RAM.
* You can also slow the run if you do not specify sufficient memory, especially if
you specify less than the default.
* You can increase the speed of the iterative solver by increasing the amount of
RAM you allocate with this option.
For specific information about specifying solver RAM, see Guidelines for Allocating
RAM for Solver and Element Data.

Guidelines for Allocating RAM for Solver and Element Data
The default values for RAM allocation for the block solver and for element data are
minimal values. If your machine has sufficient RAM and swap space available, you
may be able to improve the performance significantly by increasing RAM allocation
above the default values.
If you decide to use values other than the defaults, you can generally improve
performance by following these guidelines:
Pro/ENGINEER Mechanica - Help Topic Collection
858
* For a static or prestress analysis with the direct solver, block solver RAM should
not exceed one-half of your machine RAM. In this case, the RAM allocation for
element data has no effect and the default value is the ideal choice.
* For a static or prestress analysis with the iterative solver, block solver RAM and
the RAM allocation for element data together should not exceed three-quarters of
your machine RAM. A recommended starting point is to allocate one-tenth of your
machine RAM for your block solver and one-half of your machine RAM for
element data.
* For a modal, prestress modal, or buckling analysis, block solver RAM and the
RAM allocation for element data together should not exceed one-half of your
machine RAM. A recommended starting point is to allocate one-quarter of your
machine RAM for the block solver and one-quarter for element data.
* Block solver RAM and the RAM allocation for element data together should never
exceed three-quarters of your machine RAM.

Thanks...

Paul Korenkiewicz
FEV, Inc.
4554 Glenmeade
Auburn Hills, MI., 48326

-----End Original Message-----

iceblink1 · ‎Aug 18, 2011

It's amazing how this "black magic" setting still has not disappeared
from the software!

You should try to explain this to a new Pro/M user... and look at their
face.

PTC should set this number automatically, or at least make a better
guess automatically, and definately prevent users from setting it equal
to the amount of RAM in the workstation. (A collegue of mine did that on
a 24GB 64-bit system, and wondered why Pro/M couldn't finish the
calculation).

Just my thought on the matter.

Patrick Asselman

DamianCastillo · ‎Aug 18, 2011

Thanks for all the replies.

It seems that having our memory allocation set to 250 was not a good thing. 🙂

We changed it to 3000 or 3GB and ran the analysis again. It now runs faster and it's using up the RAM available.

I am not an expert in Mechanica, so I was not sure what I should be looking at to solve this.

Thanks for the help.

"Too many people walk around like Clark Kent, because they don't realize they can Fly like Superman"