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I have a ~1 yr old PC with a primary SSD hard drive. I notice quite often that the PC will freeze for 30secs to several minutes, displaying the "Spinning blue wheel" mouse icon during this period. It then releases and returns to normal.

When I look at the Resource Monitor during this period, I notice that the disk activity is always at "100% Highest Active Time" solidly for this period. But the actual amount of disk activity doesn't look that high to me (<1Mb per second). Memory and CPU are never remotely stressed.

Usually the anti-virus software (Kaspersky anti-virus 11.0.0.232) is the most active user of disk activity, but that doesn't seem so unusual to me. I'm typically not stressing my PC too much during these periods, just a bit of light web surfing etc.

My guess is that it is a problem with the drive, but I'm not sure what to do next (other than buy a new one).

Any ideas?

thanks,

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What model SSD? –  Mr Alpha Mar 6 '11 at 17:56
    
An "Integral SATAII and USB SSD ATA Device", capacity 121793 MB. And the driver is up to date, according to the "Update Driver" button. –  rob levin Mar 6 '11 at 19:47

5 Answers 5

up vote 16 down vote accepted

You are likely saddled with an SSD that uses the infamous JMicron JMF602 controller. The fact that it is both a SATA and a USB device is a hint, since the JMF602 is one of the few controllers with USB support build in.

The problem stems form the fact that a SSD controller can't over write data on flash memory and how your specific controller deals with it. Since the SSD controller can't over write data on flash it has to delete the old data first. But another limitation of flash is that the SSD controller can't delete a single page of data at a time, but has to delete a whole block (usually around a couple of megabytes) at a time. In order to avoid this the SSD controller rather writes the new data to a new block and marks the old data as invalid. It then does garbage collection, which is basically deleting blocks full of invalid data.

The specific issue you experience is when there are no new empty blocks to write data to when you want to write some data to the SSD. All blocks are filled with valid and invalid data. The SSD controller then has to go through garbage collection on a block in use. What it does is read all the data of a block into a cache. Delete invalid data in the cache. Delete the whole block of data in the flash. Then write the new data you are writing and the data from the cache to the now clean block. If a bunch of these happen at the same time the controller gets swamped and basically stops responding until it can clear up the backlog.

All this happens inside the SSD itself and is completely hidden from the OS. This is why non of the traditional troubleshooting techniques can find it. If all the blocks on the SSD have data on them it only takes a tiny write to force the SSD to go through the whole read/delete/write dance, so this is why you didn't see any big writes going on. Modern SSDs do not have the same problem. They have many techniques built in to avoid it, like fancy pro-active garbage collection, RAM caches and over-provisioning. They can suffer a drop in write speed, but not enough to cause the system to freeze.

The bad news is that there isn't anything you can do to fix it beyond upgrading to a good SSD. It is a design flaw in the SSD itself. You can try to minimize the amount of writes to the SSD. That would make the stuttering more rare, but not fix it entirely.

The surprising part is that in a PC only 1 year old you have one of these JMF602 based SSDs. They stopped making and selling them years ago.

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Thanks, this does sound like a very plausible explanation. The machine is actually 1.5 years old (time flies!) so maybe I got the last of a bad batch of SSDs. I'm happy to upgrade to a good SSD as this problem is really annoying. –  rob levin Mar 6 '11 at 21:50
    
Also I think the problem has got worse as I've gradually filled the drive, which also fits with your explanation –  rob levin Mar 6 '11 at 22:02
    
Are you, basically, saying that the JMicron drive doesn't support the TRIM command? Because everything you describe (empty blocks being filled, then having to perform garbage collection to consolidate blocks) sounds exactly like the TRIM command - which i understand and i'm satisfied i know the OP's problem. If you're referring to something else, i'd personally like to know more about it, and how it relates to the issues that TRIM solves. –  Ian Boyd Mar 7 '11 at 18:30
    
@Ian Boyd Yes, I'm referring to the issue TRIM is supposed to solve. Those JMicron based drives do not support TRIM. Although saying that TRIM solves it is a bit over-simplifying things. TRIM merely provides more information for the garbage collection, enabling it to run more efficiently. Completely avoiding the issue still requires a efficient enough garbage collection routine. –  Mr Alpha Mar 7 '11 at 20:51
    
Just had to say amazing answer. I understood it fairly well without being too computer literate. Excellent! –  user1125620 Apr 11 '12 at 7:09

Does the mouse also stop moving? If the mouse also isn't responding, then something in kernel mode is hogging the CPU. Otherwise the process is just misbehaving.

The next thing is to run Resource Monitor, and see if the problem is happening during paging. Check the response time of the paging operations:

enter image description here

Next we have to know if the pausing is affecting all applications, or just Explorer. If it's just explorer, then you probably have a shell extension (e.g. WinRar, 7Zip, RapidShare), or something else equally bad, interfering with Explorer. It can also be a mapped drive, or a shortcut to a network resource, and the network resource is no longer responding when Explorer tries to update the icon, or date modified, or size, etc.

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The mouse will still move. The problem does affect all apps; some will continue to work fine and others will freeze - it depends (I think) on whether the app needs to access the SSD drive during the freeze. –  rob levin Mar 6 '11 at 22:00
    
Sorry I don't have enough permissions to post a screenshot but it is not paging taking the time, it is a mix of App processes (Photoshop in my latest example) and System activities (NTFS Volume Log, NTFS Master File Table). Nothing stands out as being unusual in the processes; 148kB/sec total I/O with 100% Highest Active Time. –  rob levin Mar 6 '11 at 22:17
    
Oh, and if the issue is the drive having to perform garbage collection before it can satisfy another write operation, then the "Response Time" for writes should be high. (You can see the screenshot of response times on my SSD drive taking between 0-1ms, with response times of normal io priority on spinning C: drive as being a few dozen milliseconds. –  Ian Boyd Mar 7 '11 at 18:32

Kaspersky is the key word here. Let your scan finish, then go back and play games.

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Try this tool to see if your hard drive is failing:

  SMART and Simple for NT/2000/XP
  http://www.beyondlogic.org/consulting/smart/smart.htm

It will provide statistical information about errors and whatnot that your hard drive keeps track of.

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Thanks - I tried this but it didn't work on Windows 7. It looks a bit old - will it work for an SSD drive anyway? –  rob levin Mar 6 '11 at 19:40
    
Alternative: HDTune.com –  Tom Wijsman Mar 7 '11 at 1:28
    
rob levin: I don't know if it will work for an SSD drive. If the SSD drive includes S.M.A.R.T. technology, then it should. In NetBSD, the "atactl" command will provide access to this, so you could try booting from a Live NetBSD CD to see if you can get some answers as well. –  Randolf Richardson Mar 8 '11 at 17:02

I've seen Kaspersky do things like this at time. The memory consumption goes through the roof and this can cause heavy swapping. I've never figured out what it's up to when it does this.

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