Out of memory with plenty of memory free

[LonelyPixel]

Hi,

today my apps just don't want to run. Process Explorer says I have a "commit charge" of 45%, my system RAM is 2 GB large and there's 800 MB free. The swap file is disabled for a better system performance. I never really had a problem with that. Today, first I god the tray balloon tip saying the swap memory is low (I don't have any at all, never!) and then an application which needs 150 MB memory says it can't go on because it doesn't get sufficient memory.

So, what's going on here? Does Windows tell my Process Explorer that there's plenty of free memory but doesn't give it away when it's to be allocated? Can somebody explain what that means?

Running Windows XP MCE 2005 (XP Pro SP2)

[Irene]

Hi LonelyPixel. :)

I suppose the first thing would be to run a Virus scan.

When I had a problem similar to this, it was my virtual memory which was too low.

As I recall, there were two solutions...

#1 Increase the virtual memory to no more than (I think) 1.5x the amount of RAM installed.

#2 Allow Windows to adjust for me.

Sorry I can't offer any more, but it may be in your best interests to wait until one of the more expert members log in. :)

[LonelyPixel]

Hello Irene.

I suppose the first thing would be to run a Virus scan.

The virus scanner is permanently running in the background. And I doubt that it would find something 'cause it's been a while since I last downloaded/opened something from the internet or untrusted sources.

#1 Increase the virtual memory to no more than (I think) 1.5x the amount of RAM installed.

#2 Allow Windows to adjust for me.

I don't have *any* paging file, that feature is entirely disabled. I really have sufficient RAM, at the time when I got those problems today, I wasn't running anything that requires especially much memory (like image editing or so). Letting Windows adjust the swap file size is even worse because any resizing causes additional file system load. And Windows' IO scheduler is not the most performant anyway. I found that Mozilla applications run considerably faster after a system resume (from hibernate e.g.) or after a while minimised when there's no paging file. Also, editing a 50 by 75 cm multilayer poster is feasible with 2+0 GB whereas it's close to impossible with 1+2 GB.

[Irene]

I am sure some of the experts will be on line during the course of the day, or after work.

All the best.

[Scarecrow Man]

Lots of good info here:

http://www.petri.co.il/pagefile_optimization.htm

It's advised to use a page file, even with large amounts of system memory. Even though it is not shown as used by task manager, that does not mean the addresses are not being used. Chances are you are reaching the limit of your memory. Install more RAM or make a page file and observe the usage after.

[LonelyPixel]

It's advised to use a page file, even with large amounts of system memory.

I read from that web page that an application can request more memory than it actually uses. So the "reserved" memory amount is larger than the "commited"/"allocated" amount. Is that right? If so, Process Explorer (from SysInternals, as a replacement for Windows' Task Manager) wouldn't tell me the actual memory usage of the system. What other way is there to determine it? Also, in this case, an application would need to reserve almost 1 GB of memory without ever using it. Somehow I can't believe that.

And that page also explains that Windows only uses paging memory when RAM is out. This doesn't comply with my observation where Firefox and Thunderbird have been running considerably slower with paging memory active but not really required. I can test this again, my current HDD is a bit faster than in the past. (And there's a reboot pending due to Windows Updates anyway.)

[ɹəuəllıʍ ʇɐb]

Half of your physical memory is reserved for Windows. Even if Windows doesn't use all of that reserved space, it isn't given to applications.

I cannot imagine to run an average Windows system + applications with "only" 2GB of RAM without a page file. I wouldn't be able to run ⅟₁₀ of my applications with that configuration. Disabling virtual memory for "better performance" on a 32-bit system sounds plain silly to me...

[LonelyPixel]

Half of your physical memory is reserved for Windows. Even if Windows doesn't use all of that reserved space, it isn't given to applications.

Hm, okay, so then any known system information tools are useless for memory usage things becuase actually, less memory is available than is free. Good to know how broken Windows actually is. (Supposed you're right.)

I cannot imagine to run an average Windows system + applications with "only" 2GB of RAM without a page file. I wouldn't be able to run ⅟₁₀ of my applications with that configuration.

Oh, I can run Windows XP with a virus scanner, Firefox, Thunderbird, Psi, one or two Visual Studio 2005, VMware with a 512 MB guest OS and a couple of other applications and services (MySQL, Apache) without a problem. Memory usage raises up to 1.6 or 1.8 GB or so, but it worked in the past. With 2 GB RAM and no swap file. I only got a problem yesterday with a lot less memory usage. Maybe Windows was really just half-crashed and confused about its own memory.

Disabling virtual memory for "better performance" on a 32-bit system sounds plain silly to me...

Anyway, I have added 1 GB of swap space for now. May it be used for things that are never used. I haven't tested hibernating since then, but in the past, at least Firefox and Thunderbird have woken up after a hibernate in about 3 or 4 times the time (crawling on my HDD) than without a swap file. So this has led to reproducible and mesaurable delays. I would call that worse performance, wouldn't you?