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Many people are educated on how Windows Memory manager caching work by reading Microsoft white papers, etc. However, there are relatively few documents that describe real-world performance issues (sluggishness) related to very large/growing Mapped files and standby lists.

I have a Win7 64bit (8Gb RAM) PC which acts as a server. I can't add any more memory to it. It has a bunch of TV tuners which record/write several simultaneous gigantic mpeg2 files (at least 3-8GBs each) to HDD 24/7. Depending on how busy my PC is recordings TV shows, after 1-3 days, my PC becomes sluggish.

By just looking at Windows Task Manager, it appears that I dont have very many large applications open; and, plenty of "available memory". Even, if I close all active processes, the PC remains sluggish. However, when using RamMap, I can see that these large mpeg2 files become mapped files in the active standby list; which over time make my PC very sluggish. If I select "Empty standby list" in RamMap, my PC immediately becomes extremely responsive; as if I just rebooted it. There is nothing else I can do to address sluggishness. In fact, the PC will never recover from this sluggishness unless I empty the standby list or reboot.

I have a command-line utility, EmptyStandbyList.exe, which I found that quietly purges the standby list instead of having to do that in RamMap's GUI. However, unfortunately it also purges smaller items in the standby list that are very useful for performance purposes to stay in the standby list.

While searching on Google, I've found other people who have almost the same exact issue as me. However, most of their questions go unanswered; with no real explanation to why this happens; and, no definitive way to fix the issue other than the "Empty standby list" technique.

I've seen mentions of a MS utility/service called "Dynamic Cache"; but not sure if it cures specifically what I want. Also, the Win7/Win2008 R2 version of it seems to be only available via MS support. I also saw a couple of utilities which set the "min/max NT cache limits"; but those look like they're specific to Working sets for processes, not standby lists.

I'm hoping someone who can think outside-the-box can think of a more graceful cure for me instead of me having to use brutally empty the entire standby list regularly; and, hopefully have a definitive explanation to the symptom me (and other people) are seeing. The reason I mentioned "outside-the-box" is because there are already plenty of people who like to just recite how mapped files and standby list priorities "should" work on paper; which isn't very helpful for me.

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1 Answer 1

The Standby list is the Superfetch cache and the "Dynamic Cache" fixes a different issue. The service fixes an issue where the NTFS Metadata cache is too high. But Stadnbylist and this Cache are 2 different things. The NTFS Cache is shown as used Memory, while the Standby-Cache is contains data, but can be emptied very fast if you really new that Memory to store data in it.

On sysinternals forum the user wj32, the author of Process Hacker, created a commandline tool which does what you want:


Try it if it "fixes" your issue.

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Isn't that command line tool the exact same EmptyStandbyList.exe that the OP mentioned in his post, and for which he wants a better, perhaps more focussed alternative? –  Karan Apr 21 '13 at 17:13
Uhh... Did you read the line that starts "However, unfortunately...", and the fact that he wants "a more graceful cure"? –  Karan Apr 21 '13 at 21:07
Its nice to know there people who take the time to read the OP a bit more carefully before posting. However, I did learn a couple things I didn't know before. It sounds like what's actually causing the performance issue is related to Superfetch cache; not NTFS Metadata cache. RamMap shows both. I know under Windows vista, I had to completely turn off the Superfetch service because it didn't know how to handle TV recordings (from my DVR app); and, was causing excessive use of my HDD. I currently have the Win7 superfetch service to enhance bootup and applications I use in memory. –  user22667 Apr 21 '13 at 22:43
I'm using an SSD for my boot partition; which is only 256GB's in size. I'm curious if there are any settings in superfetch would would cure this issue; such as, suppressing certain file types from superfetch? Hopefully, someone who knows how this all works make explain why this is happening and offer an fix thats better than what I have. –  user22667 Apr 21 '13 at 22:50
Yes, I dont know either. All I know is there's an associated general system sluggishness symptom after large file standbylist activity; especially files that grow from very small to very large over time (such as video encodings, video DVR recordings, etc). I dont know of a tool that can expose what resource might be depleted due to this. Emptying the standby list completely cures the problem instantly. There are other people who can reproduce this exact behavior; and, end up using the same cure as me; without knowing why. –  user22667 Apr 27 '13 at 22:37

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