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RAM - Page File

RAM - Page File

RAM - Page File

(OP)
I dont really know much about the way RAM and the hard drive (page file) get used by SW, but recently I ran an experiment by taking 1 GB from another guy's computer and put it into mine (went from 1 GB to 2) hoping it might speed up working with some of the larger files.  But it really did seem to, at least nothing noticable.  Now, I really dont understand the page file, but the little I thought I did understand was that once RAM fills up, the page file it used as somewhat of an "overflow" for the memory usage.  But when I did this little experiment with the RAM, based on my thought for how page file worked, I would have expected the page file size to go down since I had doubled the RAM.  But it didnt, at least no by much.  Can anyone clarify any of this for me?  Is it just that 2 really doenst make much diff in this case?  Any settings that need to be changed? ?? ??? ???? Thanks for any enlightenment.

RE: RAM - Page File

In the Performance tab of Windows Task Manager, you can look at the Physical Memory area.  Check and see what the Available numbers are.  If you hit zero, you're out of RAM and writing info to your drive (slow).

If you aren't using large enough files (or running enough applications) to use up all your RAM, you'll not notice any difference in performance by adding more RAM.  However, if you're already using your available RAM, adding more (up to 2GB, unless you enable the 3GB switch) will help speed and system stability.

Are you already using your available RAM?

As for the pagefile itself, you can set the size limit within Windows properties--I don't remember exactly where.  However, I'm not convinced the pagefile size is the most relevant way to understand what's really happening within your system, so I posted the comments above.

Jeff Mowry
www.industrialdesignhaus.com
Reason trumps all.  And awe trumps reason.

RE: RAM - Page File

Having more physical RAM won't increase the speed of the system dramatically, but it will help the system to continue running at the same speed when handling larger files.

Basically Windows (32 bit) can only address 4GB ... 2GB for the OS & 2GB for applications. The 3GB switch allows aplications to address 3GB, but this restricts the OS to 1GB. This is usually not a problem but it can be.

http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx
http://swcommunity.com/feature_full.php?cpfeatureid=4372
http://swcommunity.com/feature_full.php?cpfeatureid=4475
http://swcommunity.com/feature_full.php?cpfeatureid=4602

Quote (Wayne Tiffany):


Dell 360, 3.0Ghz, 2GB RAM, swap file set to 2046K min - 4092K max:
SW2003 3GB switch off 1.98GB
SW2003 3GB switch on 1.99GB
SW2004 3GB switch off 2.00GB
SW2004 3GB switch on 3.00GB

Dell 350, 2.8Ghz, 1GB RAM, swap file set to 3072K min - 3072K max:
SW2004 3GB switch off 1.71GB
SW2004 3GB switch on 2.79GB
SW2004 3GB switch on 2.81GB (Set the max swap file limit to 4098 just to see)

Dell 350, 2.8Ghz, 1GB RAM, swap file set to 3072K min - 4098K max (a different 350 machine):

SW2004 3GB switch off 1.71GB
SW2004 3GB switch on 2.80GB
SW2004 3GB switch on 2.85GB (Upped the physical RAM to 2GB)

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: RAM - Page File

(OP)
Thanks for the input.  That's pretty much the way I thought I understood it Theo.  And Cor I hear you on the not speeding up, but I would think it would if the slow-down is being caused by excessive access to the slower hard-drive.  The thing is, when I added the RA(1GB), the page file did not change for the most part, but the Available RAM did.  It went way up, even when using this "high demand" file ( would have though that the PF would have gone down since there was now more room in RAM, creating less demand on the PF, but again, maybe my understanding is way off).  WRT to setting the PF, you can get to it starting in Systems (Control Panel) and going into the right place from there, which I have played with a little (not a lot because I really dont know what's best) based on recommendations I have come across on the internet.  i.e. I have seen to use 2xRAM, and also 1.5xRAM for min and 3xRAM for max (the latter aimed directly at SW usage).

But the thing that gets me is that the available RAM (under Task Mgr) goes up and the PF size stays the same after I add the gig.  Now in trying to understand the cryptic Microsoft world, I looked up the definition of Available Physical Memory, and this is what it says, less the elaborations:

The "Available Memory" counter in Task Manager is actually the sum of the following three internal memory lists:
•    The Standby list.
•    The Free list.
•    The Zero list.

... and blah blah blah ... the site is: http://support.microsoft.com/?kbid=312628

It is a fairly large assy but SW handles assy fine, it's the dwg, and I do get into quite a bit of detail with sections, details, etc (which I know is hard on SW), is it pretty much a limitation of the software and computer?

Is my system seem adequate.

My system is (I dont understand implications of most of it, so including as much as I can):

Dell Precision PWS380
1GB RAM
Pent 4, 3GHz
XP SP2
RAM speed 667MHz
Proc Bus Speed 800 MHz
L2 Cache 2GB

Thanks again, I dont mean to dump too much out, but the SW performance optimization thing is really a thorn in my side in terms of what to do and then know that is is running as smoothly as possible with current resources.

Thanks,
I really appreciate your time and input,
Mike

RE: RAM - Page File

(OP)
Also, video is:

NVIDIA Quadro FX 1400

What is the 3GB switch?  Is it some that is controllable, or is it an MS automatic feature?

RE: RAM - Page File

"What is the 3GB switch?"
Check the links I posted.

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: RAM - Page File

It may be helpful to think of the page file as space on the hard drive set aside to for use as RAM overflow.  Windows likes to have that space set aside when it starts, and you can pick the initial and maximum size, or let Windows manage it.  Windows can increase the size of the page file while running.  It will pop up warning boxes whenever it has to, so I guess this is an operation that is to be avoided when possible.

It is not surprising that you did not see a decrease in the size of the page file when you increased the amount of RAM in the system, as the size of the page file is just how much space has been reserved for paging out RAM.  What you should see is an increase in available physical memory and or a decrease in page file usage, as seen on the task manager.

Windows tries to balance keeping physical RAM available with minimizing access to the page file.  This means it will generally have some stuff in the page file even when there would be room in RAM for everything.  This makes it difficult to have cut and dried rules for when adding RAM will help performance.  I would guess that if your page file usage while working on your assemblies or drawings is more than 800MB or so, adding RAM is likely to help.  The dead give away is when you do something that does not directly involve disk access and you have to wait while the hard drive grinds away.

RE: RAM - Page File

(OP)
I guess that's pretty much how I viewed the PF.  When I first load SW, PF is around 800, if I remember correctly, but when I load this file, currently I am over 1.5GB for PF Usage with 1GB RAM, but when I did my experiment with 2GB, it was pretty much the same PF usage as with 1GB; and the performance was not noticably affected.  I was wondering if my results of adding the additional gig for my situation could be justified with the analogy of: trying to catch 10 gallons of water with a 2 gallon bucket vs a 1 gallon bucket would be no different even though the 2 gallon is twice as big.  Meaning maybe I would need even more RAM to see a performance dif in this situation???  Just a curiosity ... or maybe it's more of a situation that it's just crunching THAT much data, and there is always a limitation ... just typing what comes across my head ... Cor, I did follow the link orig, but it required a login which I didnt have and I didnt set up an account yet (it requires a lot of info, I usually dont like to put too much out there, but I probably will eventually).

Does my system seem adequate based on specs I gave up there?

Some stuff I read of SW site said 1GB min if dealing with assy's >1000 components. Mine is more, so I am assuming that even if adequate I'm kind of marginal with it.  Most assy's are not this large, but some.  And again, it seems to handle assy quite well, just the dwg when I start adding all the detail.

Thanks All

RE: RAM - Page File

Yes, your system specs are OK, but 2GB RAM would definitely make things better. Setting the VM to 4096MB (Min & Max) will not hurt either.

Quote:


The virtual address space of processes and applications is still limited to 2 GB, unless the /3GB switch is used in the Boot.ini file. The following example shows how to add the /3GB parameter in the Boot.ini file to enable application memory tuning:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINNT="????" /3GB

If you are always going to be dealing with large assy files, then you might want to consider upgrading to XPx64 and SWx64 so that even more RAM can be used. The /3GB switch would then be unnecessary ... in fact it would be detrimental as it would restrict the x64 systems.

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: RAM - Page File

How much Available Physical Memory do you have when this assembly is open?  That's the most direct way I know to see whether you're using all your current RAM or not.  From what you posted above, you have plenty of RAM available when the large file is open--hence, more RAM won't do you any good until you're reaching/exceeding your current potential.

Jeff Mowry
www.industrialdesignhaus.com
Reason trumps all.  And awe trumps reason.

RE: RAM - Page File

(OP)
                    Phys-Mem-Avail PF-Use SW-Mem(Processes)

Before open SW       776800 K       316MB     n/a
After open SW        565700 K       502MB     195256 K
After open slddwg    41488 K        1.25GB    490000 K

That's with 1G RAM, but when I added the additional Gig it pretty much added it to the existing available.  I see what you mean in that there is some RAM left, but not much and with how slow it's running, I hoped it was a matter of getting more RAM.  I would assume that Avail RAM is never brought down too close to 0 for stability reasons and with how large the PF got, I assumed it was part of the overflow.  I really dont know how all the memory gets allocated and utilized though so I guess that's where it is.

Thanks,
Mike

RE: RAM - Page File

If you go to the Processes > View > Select Columns, you can select other options to show. One of them is Virtual Memory Size which may be more useful in seeing the actual VM for each process running.

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: RAM - Page File

(OP)
Ah, very nice ... did not know about that.

During one of my naptimes I mean processing times, SW data is:

Mem Usage: 335 MB
VM Size: 1.5 GB

RE: RAM - Page File

FYI, even if a process has no need to use VM, Windows will allocate VM space for that process ... just in case.

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: RAM - Page File

(OP)
Thanks.  Another thing I have noticed is the CPU usage, which I assume unlike the PM and VM showing allocations and not necesarily activity is more of a real-time/actual performance number. Is that correct?  And if so (and sounds like this is not uncommon) mine rarely gets over 50% (which is a high number) these slow times even when the only other call for processor is coming from the idle process.  Also, during those very slow times of loading or saving or updating, the % shown usually goes to 0 at some point which to me indicates SW pulling over for a pit stop or something - if that number really has a real-time meaning

1st - I assume this is based on what SW is asking of the processor based on need (ie memory availability/speed and software operation), and if so, is there a way to optimize this

2nd - Is there a CHANCE this indicates a level of corruption?

If I take off in the wrong direction with any of that just yell at me.

Thanks,
Mike

RE: RAM - Page File

It looks like you have hyper threading enabled on you machine.  It is a processor option that makes 1 processor appear as two, with the side effect that most programs can then use only 1/2 of the processor.  You should be able to disable it through the BIOS.

Eric

RE: RAM - Page File

Quote (EEnd):

It is a processor option that makes 1 processor appear as two, with the side effect that most programs can then use only 1/2 of the processor.
That's not quite how it works. Normally, a single processor will be able to do a certain number of things at a time (because there are several parallel components on a CPU, some duplicated, some unique). Hyperthreading allows two threads (separate groups of instructions; programs will often have many threads) to execute simultaneously, because some resources are duplicated (for more speed and bandwidth). The catch is, when something that isn't available in duplicate is desired, one thread has to wait. Also, there's additional work that's necessary to co-ordinate this, so depending on the task, you may or may not see an improvement. But the key is, programs aren't really using 1/2 of the processor.

RE: RAM - Page File

(OP)
Thanks Eric and Fed,

I did go and disable, and in some very small ways it was faster, but it was definitely more stable.  For whatever it means, the CPU usage got up to some very high levels too.  I will stick with that setting to see how it goes.  It is definitely not worse.

I really appreciate all the input. Seems like I'm about as good as I can be short of improving system, improving my SW practices, and having someone come in and make sure everything is optimally set.

I think I learned a lot on this one.

Thanks,
Mike

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