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According to this, disk queue length is the number of hard disk requests stacked up.

I have a laptop with a SSD drive. The disk queue length consistently gets up over 10.00 when doing things like loading programs. (Outlook, firefox, etc). Other computers have an average of a hundredth -- 0.01 that sometimes goes to 0.10. This is with a traditional hard disk.

What is the symptom of this? Everything seems to tell me that the SSD is in good health and these things don't fragment (per my understanding).

So, what might this be or how can I solve this? Said computer is just a pain to use... Is this simply a bad or failing SSD drive?

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Depending on your situation, e.g. if your Windows 7 install was migrated from another disk rather than done fresh on the SSD, you may need to investigate SSD partition alignment (e.g. sevenforums.com/tutorials/113967-ssd-alignment.html); read/write request splitting could potentially result in this kind of isusue. –  Aaron Miller Mar 28 '13 at 16:45
    
Windows was installed on the SSD directly. In fact, this computer has been in service for a couple of years now. The "slow" issue has only come up in the last couple of months and only yesterday did I isolate it to the high disk queue length. This computer used to be really fast. Now it's the slowest computer I have... –  Frank V Mar 28 '13 at 16:50
    
Wait -- would a hard drive encryption utility tweak the partitions? Given your article, I see 3 partitions. The main one (where windows is ran from) is at off set 140 MBs (is what it says.) –  Frank V Mar 28 '13 at 16:54
    
I am not sure what is cause and what is result. A slow disk would lead do request arriving faster than they get handled and thus a high queue depth. (In which case the high Q.D. is a result, not the cause). –  Hennes Mar 28 '13 at 17:04
    
what is the make and model of the ssd? –  cybernard Apr 3 '13 at 23:02

1 Answer 1

Root cause can be one of these:

  • you have "Virtual Memory" turned ON. Using "Virtual Memory" on SSD deteriorate system performance. Experiment with turning it off.

  • RAM of your PC is too low, especially if it is 2GB or less, your system will heavily depend on virtual memory which entirely hamper Disk I/O performance.

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Virtual Memory would affect performance even more on mechanical HDDs, as they are way slower, right? –  gronostaj Dec 31 '13 at 11:05
    
@gronostaj slower is right. but their read/write don't affect lifetime, which in case of SSD isn't true. so, minimize read/write count, manufacturers recommend no to use virtual memory if you want maximum reliability. by "SSD deteriorate system performance" , i meant that using that i suffered a stuck problem. for some mysterious reason, my system used to "hang" in every 2/3 minute for appx. 30 seconds. Just turning off VM solved that problem like magic –  kmonsoor Jan 1 at 22:50

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