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I ran into a problem with very large image files. 700MB-3GB. When I click on them, my memory usage spikes. If the file is hosted on a network drive, the network usage jumps to 25% of a gigabit LAN connection.

This is just clicking on the file. It continues until the loading bar at the top of the explorer windows is done loading. If you click multiple files, the system will slow to a crawl and network usage will jump to 50%.

This is an i7 with 8GB of RAM running Win7 64bit. And it becomes un-usable until that loading bar is finished. I have tested it on a lower end system running Win7 32bit, I get the same results, only my whole computer locks up until its done.

Again, this is just clicking on the image files. I have it in detail view. I have also gone through the steps of disabling all thumbnails & thumbnail caching. And I have turned off all of the Aero interface to remove any sort of preview that WIn7 may be generating.

I again tested this on my home system and it did the same. And when I asked the question on Google+ I had someone else offer to help, they reported back the exact same results. They also tested in a Win8 preview they had and found that Win8 also does this.

Someone did some testing and found that it also does this to very large MPEGs as well.

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Curious. What are the specs and OS of the machine host? – surfasb Oct 5 '11 at 22:24
What is exactly your question? You explained something, but didn't actually ask anything. – haimg Oct 5 '11 at 22:47
Specs are in there. So is OS version. Are you kidding @surfasb? No, i never stated a question @haimg, your right. Are you just fishing for some easy points? My "Question" would be "How can I make Windows 7, not slow down and consume crazy amounts of resources, just because I clicked on a large image file?" It may also be "Why does Windows 7 do this?" It could also be "What 'super helpful feature' in Windows 7 is doing this, and how can I disable it?" Because you can't seem to find these yourself, I seriously doubt your the right person to be looking at this anyway. Thank you though. – Christopher Oct 6 '11 at 12:50
@haimg: Call me crazy but I just assumed the OP wants to actually use his computer like normal instead of the OS caching the image of the file, etc etc. Maybe I am crazy and people find this acceptable? – surfasb Oct 6 '11 at 16:15
@Christopher: My bad. I meant the OS and specs of the host of the files. – surfasb Oct 6 '11 at 16:20

These are the two most probable reasons for this behavior, in my opinion:

  1. In detail view, Explorer still has to hit the files for image metadata. Granted, to get image details all the image does not have to be read, but as soon as Explorer accesses the file, your antivirus kicks in and reads the whole file across the network for virus scanning. How to test if you have this problem: disable your antivirus, temporarily.

  2. There is a badly written shell extension installed, that accesses your files when it shouldn't. It may be a legitimate one, or some kind of malware. Install Autoruns for Windows (free) which lists all installed shell (explorer) extensions. Disable what seems suspicious to you (temporarily) and see if that helps.

Good luck.

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My only guess is this is due to Offline Files trying to cache the file for future uses. Which is strange, because I don't see the same behavior when I click on large MPEGs and MKVs.

For the record, I've tried server hosts of server 2003, 2008, and 2008R2 and haven't reproduced the behavior.

You can turn off Offline Files and test it, since I cannot reproduce the behavior with either large PDFs, or large JPEGs.

If you go under GPEDIT.msc then Computer Configuration/ Admin/ Network, try turning off Transparent cache and Slow link mode.

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I know this question was posted a few years ago, but I think I know the reason why this is happening.

It's because Windows is automatically asking remote CIFS/Samba server for information about the file you've clicked. It happens placing the pointer of the mouse over the file, too.

Hope this helps somebody.

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