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Processor

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Hi,

I'am getting a new workstation DELL T5500, quadcore, 4GB Ram, Nvidia Quadro FX graphics card. I am being told by my IT colleagues that for 4 GB Ram, a 32 bit OS should be sufficient. I tried telling them what i've read in this forum "in order to address all the memory you need a 64 bit OS" but they dont agree with me.

Could somebody tell me if 32 bit is actually sufficient for 4GB ram. If not I'll try pushing my case harder.

On a standard dual core, 2GB RAM, 32 bit OS, my simulations take up to 6-8 hours to complete. Am hoping it reduces by a good extent using the workstation.

Thanks.

10 Replies Last Post Jan 25, 2011, 10:31 AM EST

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Posted: 1 decade ago Oct 11, 2010, 9:33 AM EDT
If you have 4GB of RAM in your system (or more), and you want to take full advantage of it, start using a 64-bit OS.

If they know something else, let me know too. I am curious.

Danial

--
Comsol 4.0a
Ubuntu 10.04.1
If you have 4GB of RAM in your system (or more), and you want to take full advantage of it, start using a 64-bit OS. If they know something else, let me know too. I am curious. Danial -- Comsol 4.0a Ubuntu 10.04.1

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Posted: 1 decade ago Oct 11, 2010, 4:59 PM EDT
You should point your colleges to knowlege base articles on the subject, such as: www.comsol.com/support/knowledgebase/866/

Using all of that 4 Gb of memory will require a 64 bit OS. I happen to have a Windows 7, 32 bit system with 4 Gb of ram installed handy and "System Information" shows:

Installed Physical Memory (RAM) 4.00 GB
Total Physical Memory 3.46 GB

Indicating that at least with Windows 7, not all of the RAM is available. Note that the 4 Gb limit that 32 bit operating systems have is shared between the system RAM and other things such as video card memory. Also, Windows 7 32 bit has a limit for memory per process of 2 Gb.

Using the 64 bit OS would make it easier to add memory to your system later on as well. Also, you may want to consider using linux, as that seems to do a better job of handling memory (at least in my experience).

You should point your colleges to knowlege base articles on the subject, such as: http://www.comsol.com/support/knowledgebase/866/ Using all of that 4 Gb of memory will require a 64 bit OS. I happen to have a Windows 7, 32 bit system with 4 Gb of ram installed handy and "System Information" shows: Installed Physical Memory (RAM) 4.00 GB Total Physical Memory 3.46 GB Indicating that at least with Windows 7, not all of the RAM is available. Note that the 4 Gb limit that 32 bit operating systems have is shared between the system RAM and other things such as video card memory. Also, Windows 7 32 bit has a limit for memory per process of 2 Gb. Using the 64 bit OS would make it easier to add memory to your system later on as well. Also, you may want to consider using linux, as that seems to do a better job of handling memory (at least in my experience).

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Posted: 1 decade ago Oct 11, 2010, 5:11 PM EDT
Hi,

Thanks for all the replies.

I noticed that there is something called 4GT (4 gigabyte tuning) by which we can allow the maximum physical memory used by a process to go up to 3 GB (from the 2GB limit set by Windows Vista 32 bit).

Has someone used this before ? Could you let me know the method to change this ?

Thanks !
Hi, Thanks for all the replies. I noticed that there is something called 4GT (4 gigabyte tuning) by which we can allow the maximum physical memory used by a process to go up to 3 GB (from the 2GB limit set by Windows Vista 32 bit). Has someone used this before ? Could you let me know the method to change this ? Thanks !

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Posted: 1 decade ago Oct 12, 2010, 9:19 AM EDT
I'd be curious to hear if it works out for you or if someone else has tried it out. However, I would be surprised as the memory made available using the 4GT switch will not increase the size of largest contiguous block of memory available to the solver. (There are some knowledge base articles on the issue, including the one I listed in my last post.)

From: "4-Gigabyte Tuning" msdn.microsoft.com/
-Addresses near the 2-GB boundary are typically used by various system DLLs. Therefore, a 32-bit process cannot allocate more than 2 GB of contiguous memory, even if the entire 4-GB address space is available.

If you're trying to improve performance in your current system, you might want to try running in client/server mode. This gets around the per process limit by running COMSOL in two processes (one for the GUI, one for the solver). Also, if memory is your issue, you could try out readyboost. There are more discussions on the community forum that you might want to look over.

I'd be curious to hear if it works out for you or if someone else has tried it out. However, I would be surprised as the memory made available using the 4GT switch will not increase the size of largest contiguous block of memory available to the solver. (There are some knowledge base articles on the issue, including the one I listed in my last post.) From: "4-Gigabyte Tuning" http://msdn.microsoft.com/ -Addresses near the 2-GB boundary are typically used by various system DLLs. Therefore, a 32-bit process cannot allocate more than 2 GB of contiguous memory, even if the entire 4-GB address space is available. If you're trying to improve performance in your current system, you might want to try running in client/server mode. This gets around the per process limit by running COMSOL in two processes (one for the GUI, one for the solver). Also, if memory is your issue, you could try out readyboost. There are more discussions on the community forum that you might want to look over.

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Posted: 1 decade ago Oct 14, 2010, 2:32 PM EDT
Hi,

I got my new processor. Its the DELL T5500. Runs on an Intel Xeon CPU E 5506 @ 2.13 GHz 2.13 GHz (2 processors)
Installed RAM 4GB (3.25 GB Usable), 32-bit Operating System, Windows 7.

I earlier had 2GB Ram and while I used to run simulation (in HIGH PRIORIITY mode) other applications used to hardly work. With this one, that problem is solved. But I am still amazed to see that my simulation time is hardly faster. There's no difference. Any comments ?

Also, I dont find any graphics card installed in it. NVidia FX Quadro was supposed to be installed in it though. Any way by which I can check this ? Is this why my simulations show no improvement ?
Hi, I got my new processor. Its the DELL T5500. Runs on an Intel Xeon CPU E 5506 @ 2.13 GHz 2.13 GHz (2 processors) Installed RAM 4GB (3.25 GB Usable), 32-bit Operating System, Windows 7. I earlier had 2GB Ram and while I used to run simulation (in HIGH PRIORIITY mode) other applications used to hardly work. With this one, that problem is solved. But I am still amazed to see that my simulation time is hardly faster. There's no difference. Any comments ? Also, I dont find any graphics card installed in it. NVidia FX Quadro was supposed to be installed in it though. Any way by which I can check this ? Is this why my simulations show no improvement ?

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Posted: 1 decade ago Oct 15, 2010, 9:09 AM EDT

I got my new processor. Its the DELL T5500. Runs on an Intel Xeon CPU E 5506 @ 2.13 GHz 2.13 GHz (2 processors)
Installed RAM 4GB (3.25 GB Usable), 32-bit Operating System, Windows 7.

Your best bet would probably be to switch to a 64 bit operating system to better utilize your available memory, and buy some more RAM (it's pretty cheap these days). Installing a dual boot with linux would be an easy way to try it out. Also, am I reading your post correctly that you have 2 Xeon processors for a total of 8 cores (16 logical if using hyperthreading)? You could track your memory usage with task manager to see what's happening. If virtual memory is being used that will slow things down dramatically (virtual means using hard disk as memory in this case).


I earlier had 2GB Ram and while I used to run simulation (in HIGH PRIORIITY mode) other applications used to hardly work. With this one, that problem is solved. But I am still amazed to see that my simulation time is hardly faster. There's no difference. Any comments ?

You could try setting the -np command or running in batch mode. By sticking with the 32 bit operating system, you probably didn't make any difference in the amount of contiguous memory available for the solver.


Also, I dont find any graphics card installed in it. NVidia FX Quadro was supposed to be installed in it though. Any way by which I can check this ? Is this why my simulations show no improvement ?

The graphics card is used for graphics, the plots on the screen, etc; not solving the model so it should make no difference. Well, except with a 32 bit operating system, the amount of graphics memory is subtracted from the amount of ram available.
[QUOTE] I got my new processor. Its the DELL T5500. Runs on an Intel Xeon CPU E 5506 @ 2.13 GHz 2.13 GHz (2 processors) Installed RAM 4GB (3.25 GB Usable), 32-bit Operating System, Windows 7. [/QUOTE] Your best bet would probably be to switch to a 64 bit operating system to better utilize your available memory, and buy some more RAM (it's pretty cheap these days). Installing a dual boot with linux would be an easy way to try it out. Also, am I reading your post correctly that you have 2 Xeon processors for a total of 8 cores (16 logical if using hyperthreading)? You could track your memory usage with task manager to see what's happening. If virtual memory is being used that will slow things down dramatically (virtual means using hard disk as memory in this case). [QUOTE] I earlier had 2GB Ram and while I used to run simulation (in HIGH PRIORIITY mode) other applications used to hardly work. With this one, that problem is solved. But I am still amazed to see that my simulation time is hardly faster. There's no difference. Any comments ? [/QUOTE] You could try setting the -np command or running in batch mode. By sticking with the 32 bit operating system, you probably didn't make any difference in the amount of contiguous memory available for the solver. [QUOTE] Also, I dont find any graphics card installed in it. NVidia FX Quadro was supposed to be installed in it though. Any way by which I can check this ? Is this why my simulations show no improvement ? [/QUOTE] The graphics card is used for graphics, the plots on the screen, etc; not solving the model so it should make no difference. Well, except with a 32 bit operating system, the amount of graphics memory is subtracted from the amount of ram available.

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Posted: 1 decade ago Oct 16, 2010, 7:17 AM EDT
Hi John,

Thanks for your time for all your replies. They were most helpful.

Yes I have two processors so total of 8 cores (i checked the Environment Variable NO_OF_PROCESSORS). I dont think it has HTT though.

The CPU and RAM usage oscillates a lot. CPU varies from 14% to 95% within every few seconds. I've attached a few screenshots.

I think its sensible that the Physical Memory never crosses 1.5 GB because only 2GB is allowed per process on 32-bit (of my total 4 GB) ?

But the Memory in the Task Manager processes page (Private Working Set), never crosses 0.5 GB.

Regards,
Harish
Hi John, Thanks for your time for all your replies. They were most helpful. Yes I have two processors so total of 8 cores (i checked the Environment Variable NO_OF_PROCESSORS). I dont think it has HTT though. The CPU and RAM usage oscillates a lot. CPU varies from 14% to 95% within every few seconds. I've attached a few screenshots. I think its sensible that the Physical Memory never crosses 1.5 GB because only 2GB is allowed per process on 32-bit (of my total 4 GB) ? But the Memory in the Task Manager processes page (Private Working Set), never crosses 0.5 GB. Regards, Harish


Ivar Kjelberg CSEM SA (CH)

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Posted: 1 decade ago Oct 16, 2010, 10:40 AM EDT
Hi

first of all try the task/process manager of www.sysinternals.com (you should be redirected to Microsoft as they have bought out the guy and all his good stuff ).

2nd note that the solvers are oscilalting between different operations and not all can be parallelised, this results often in oscillations between 1 processor active and all processor active, at a frequency depending on the size of the model

3rd not all solvers can use several processors for their task

4th, since a MS update a couple of months ago, I have noticed that it looks like MS is not allowing all processors to go full speed over long periods, at least something has changed since this summer on my VISTA's memory management, but I did not record my screen views so it's hard to compare fully

--
Good luck
Ivar
Hi first of all try the task/process manager of www.sysinternals.com (you should be redirected to Microsoft as they have bought out the guy and all his good stuff ). 2nd note that the solvers are oscilalting between different operations and not all can be parallelised, this results often in oscillations between 1 processor active and all processor active, at a frequency depending on the size of the model 3rd not all solvers can use several processors for their task 4th, since a MS update a couple of months ago, I have noticed that it looks like MS is not allowing all processors to go full speed over long periods, at least something has changed since this summer on my VISTA's memory management, but I did not record my screen views so it's hard to compare fully -- Good luck Ivar

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Posted: 10 years ago Jan 25, 2011, 10:10 AM EST
Dear sir ,
Iam using windows vista as my operating system ..when i am running comsol 3.5 on my system i am facing problems like low memory most of the time .. when i use to solve a model i am unable to see animated version of that model ... Can u figure out the problem which i encountered ....Please do let me in quick span of time ...

I am enclosing my system configuration below
Processor : Intel core 2 Duo CPU T6400 @ 2.00GHz
Memory : 3GB(RAM)
system type : 32-bit operating system


Krishna Chaitanya ...
Dear sir , Iam using windows vista as my operating system ..when i am running comsol 3.5 on my system i am facing problems like low memory most of the time .. when i use to solve a model i am unable to see animated version of that model ... Can u figure out the problem which i encountered ....Please do let me in quick span of time ... I am enclosing my system configuration below Processor : Intel core 2 Duo CPU T6400 @ 2.00GHz Memory : 3GB(RAM) system type : 32-bit operating system Krishna Chaitanya ...

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Posted: 10 years ago Jan 25, 2011, 10:31 AM EST
The performance depends on the model you are running. Is it 3D or 2D? Because 3D generally required a lot more memory.

Also, try using a coarser mesh first and try obtaining a solution.

For the system specs, you could try changing to 64 bit. This generally is supposed to be better.
The performance depends on the model you are running. Is it 3D or 2D? Because 3D generally required a lot more memory. Also, try using a coarser mesh first and try obtaining a solution. For the system specs, you could try changing to 64 bit. This generally is supposed to be better.

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