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Sometimes my Windows 7 system is accessing the hard drive heavily for several minutes and it slows down the machine considerably.

Is there a tool which tells me which process is causing it? That includes if Windows is accessing the virtual memory? I tried SysInternals' DiskMon but it doesn't show useful information, like the process. The Task Manager shows some I/O counters but I still can't determine which one is doing it the most. Plus it doesn't show virtual memory access.

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migrated from Oct 6 '10 at 6:03

This question came from our site for system and network administrators.

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"What's my computer doing?" :

Perhaps even you are curious why your hard disk LED is sometimes flashing. Or why the CPU fan gets louder even if you're not doing anything.

The free software "What's my computer doing?" tells you why. It shows all programs (with details!), that are accessing your hard disk or using the CPU. Furthermore you have the option to close these programs or even uninstall them.

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How is this any better than the Task Manager? It does exactly the same thing, only with less information provided. – Chris Pratt Dec 19 '13 at 17:05

Resource Monitor can do this and is built into Windows 7. You can access it from a button in Task Manager's Performance tab.

Once you open Resource Monitor, expand the Disk Utilization drop-down. It will show you what processes are accessing the disk. On the Disk tab you can get more detailed information about which processes are utilizing how much disk I/O, among other stats.

Resource Monitor from Task Manager

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But how to use Resource Monitor? If I look under Disk tab and sort by "Total (B/sec)", it's always "System" and "C:\pagefile.sys" at the top which isn't helpful. – endolith Nov 6 '15 at 14:43

As @weloytty says, the Resource monitor will help. You can also check Process Explorer from MS/systernals Process Explorer

By any chance are you running Skype on this system? If so, has it become a supernode and you are now having all that traffic? Quit Skype and be sure that the icon does not remain in the Notification Area. Even if you cannot receive calls, it can still be running

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I am, in fact, running Skype; it's required for my job. Grrr. – David Lively Oct 26 '11 at 18:40
There is a fix for this but I can't seem to get teh link to work with full document. There is a registry fix Please backup before making any change and I will try and fid the document Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Skype] [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Skype\Phone] "DisableSupernode"=dword:00000001 – Dave M Oct 26 '11 at 19:37
It used to be described here but the actual registry change instruction is now missing. – Dave M Oct 26 '11 at 19:42

Go to Control Panel\All Control Panel Items\Performance Information and Tools\Advanced Tools and start Resource Monitor. You can see what's hitting the disk there.

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Thanks! I learned that it can also be opened from the command line – Xv. Oct 25 '14 at 16:55

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