Memory usage at 100% in Windows 7

Daniele Brunengo
Daniele Brunengo used Ask the Experts™
on
Hello, I have a peculiar problem in my W7 Ultimate 64bit install.

Lately, once in a while memory usage goes up to 99-100%, and then it goes back down with no apparent reason.

The strange thing is, task manager will show normal memory usage, with the sum of all processes adding to a number far below 6Gb. And yes, it is configured to show processes from all users.

I initially thought that it was Firefox 4.0, because the first time this happened I closed Firefox and usage went back to normal almost instantly.

But then it happened again, and closing Firefox wasn't useful, still had to wait a few minutes for the situation to fix itself.

Is there a way to find out the cause of this?
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Commented:
A friend of mine had such a problem and we found out that it was a Microsoft Security Essentials that was eating all the CPU. We removed it and everything has come back to normal again, with 2-4% CPU usage when idle.
can u try Resmon.exe tool in win7
Go to Start->type in Resmon.exe and start the tool

check which proc takes maximum memory usage and take necessary steps.

Commented:
Would recommend to use process explorer to find out the faulty software.

http://technet.microsoft.com/en-us/sysinternals/bb896653


Also can try clean boot to find out the faulty software.

Clean boot process

Start-type - msconfig- click on startup tab- click disable all...then click services tab- put a check on hide all microsoft services ...and then click disable all....click ok and then restart the computer in normal mode.

If everything works fine in clean boot then enable five startup items and services at a time to find the faulty software.



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Look in process and see what is slaying the memory. Will you let us know?
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
@phackwer: I'm not using Security Essentials, but anyway I'm talking about ram, not cpu.

@sanjithml and jarrod_williams: I already checked with Task Manager and Resource Monitor but the processes listed all use a normal amount of memory, as stated in the description. The sum of all memory used by all processes doesn't amount to 25% of total ram, but the indicator says 100% of physical memory is used and the computer is sluggish as hell when this happens. That's what's makes this problematic, I have no way to determine which process is the culprit, at least with the usual resource monitor.

I will try with process explorer as soon as this happens again, maybe also process monitor to see if there's something quirky going on.
Something is holding onto the memory. Does it only happen when  Firefox  is open? or does this happen with other programs aswell?
Of course you need to try the tools when the problem occurs else you wouldn't find the culprit.

Just observe the time at which it happens. some times virus can be active only on particular time and cause the problem.
if it happens daily at particular time then it can be malicious virus.

Keep that in mind too.. and let me know the status.
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
@sanjithml: of course I used the tools while the problem was happening, that's why I posted here. It's a strange thing when no process seems to be using too much ram, and yet the memory is maxed out. I will check if the time is always the same when it happens.

@jarrod williams: I usually have Firefox open all the time, so yes I'm almost positive it always happened with Firefox open. I read on some forums that Firefox 4.0 has a memory leak problem on some systems. Should a memory leak show up in Task Manager as an abnormal amount of occupied ram, or does it work behind the os' back and hide the true amount of utilized ram?

i see.
i suggest you use security task manager also.

http://www.neuber.com/taskmanager/taskmanager.html
Have you checked in the event log for any dodgy errors or warnings? that could help narrow the search?
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
Yes I checked but there was nothing strange around the time of the problem. There are no errors or warnings for the whole morning.

I'll check out that security task manager, looks very interesting.
Donald BarkerManager, Endpoint Security

Commented:
Which AV are you using and are you running any products such as LanDesk or Altiris?
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
The Antivirus is G Data Antivirus 2011. No I'm not using LanDesk or Altiris.
If no tasks are listed that are eating up your ram then I would worry about a rootkit virus which has the ablility mask itself.

When I run into rootkit viruses that are being missed by the antivirus I remove the hard drive and install it as a secondary drive in another system.  That way the virus is not running and therefore cannot mask itself.  I empty all the temp folders on the drive then run a virus scan.

Always make sure the system that you are installing the drive into has a current anti-virus so it can protect itself.

I also sort the files by time and date in the Windows folders and look for any new files that don't belong.  I then remove or rename them.  This can get tricky because not all new files are bad ones.  If you are not sure about a file you should search for it on the internet to see what program may be using it.
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
Instead of removing the drive I booted from an external drive which is partitioned with the Sardu multiboot rescue system, I tried 3 different antiviruses (Avira, BitDefender, Kaspersky) but there's nothing of that sort.
is it a laptop or desktop?
how many memory module u got?
can try with 1 module and try?
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
Desktop. I will test the modules with Goldmemory and report back tomorrow.
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
No bug found in any memory bank. Today it happened again, and again Firefox was open. I guess it may be a Firefox memory leak after all.
urlclassifier3.sqlite file under Firefox profile folder can create such problems.
try deleting it.

Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
I tried deleting the file, then ran the tool. Let's see what comes out of it.
Daniele BrunengoIT Consultant, Web Designer

Author

Commented:
I've had no more trouble in the last few days. The last suggestions about Firefox were right on track, thanks.

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