scanclank

I have been digging around and this seems to be be a can of worms. Manufacturers and users are now having to acknowledge that SSD performance IS affected by fragmentation Long article about effects of Intel SSD fragmentation here Many more articles here Summary: There are 2 kinds of fragmentation that concern SSD disks. The first kind of fragmentation is memory block fragmentation. SSD disks are written in pages (generally 4KB in size) but can only be erased in larger groups called blocks (generally 128 pages or 512KB). This causes fragmentation and results in severe performance loss after the disk has been used for a while. Speed can easily drop by 50% or more. The SSD manufacturers have developed a solution called the TRIM instruction, (see Wikipedia article). This is a hardware solution that needs support in the operating system (windows 7 on), and only applies when files are being deleted. It is not used with SD cards, or with cameras, camcorders & Ipods etc. The second kind of fragmentation is file system fragmentation. Files can be split into numerous data chunks that are placed anywhere in the SSD memory, just like on hard disk platters. Many users believe the hype that this kind of fragmentation does not matter for SSD disks, because the disks have a very low 'seek' time. But all operating systems, (whether camera or Windows) still have to do more work to gather all the fragments when a file is fragmented . There are extra I/O operations and these take time, as does identifying and using many fragmented storage locations when writing. This is made worse by windows NTFS, designed for HDD. Quote: ..."The problem goes back to the NTFS file system, which is employed by all current Microsoft operating systems. This file system is optimized for hard drives, but not for SSDs. As data is saved to an SSD, free space is quickly fragmented. Writing data to these small slices of free space causes write performance to degrade to as much as 80 percent -- and this degradation will begin to appear within a month or so of normal use. The problem erodes speed, which is of course a primary value of an SSD..." And the SD card developers organisation says: "The memory of a card is divided into minimum memory units. The device writes data onto memory units where no data is already stored. As available memory becomes divided into smaller units through normal use, this leads to an increase in non-linear, or fragmented storage. The amount of fragmentation can reduce write speeds, so faster SD memory card speeds help compensate for fragmentation." (Source: here) -So the solution is to keep buying faster cards to mask the problem?!!?.. Oh, that's alright then...

redhawk - Thanks again for your reply. As I also explained earlier, I fully understand your comments, and agree that the 'copy off, copy back' method works well for this task. My original post was prompted by the Piriform invitation to "Tell us what you think". It was my experience of using this software for this particular job. I realise that it it does better with spinning platters... -'nuff said now, I think. (It's a class 4 card BTW)

redhawk - I don't know about your camera memory cards, but mine tend to stay in the camera either until they are full or until I feel the need to empty a card for a coming event, or until my conscience says back 'em up and clear them. Augeas - Digital cameras compress from RAW to Jpeg and the size per image varies with content. If you then review and delete duff images, you are left with free space distributed across the card. The camera then recovers this space and re-writes to these areas, maybe with a larger size image which is then split across these patches = serious fragmentation. If you also record and delete video, (the large file on my card above) things get even worse. This does slow down camera performance as I mentioned. I happened to have a card plugged into my PC today whilst trying this software. It offered to defrag it, and so I gave it the chance. I understand the problems involved, but I still would not expect defrag software to actually more than double the fragmented file count. By experimenting I found that this total reduced to 12 after three more passes, then no further improvement. For reference, another defragger then reduced this to 6.

Sorry Moderator, I must disagree. Fragmented cards make a BIG difference to both the camera startup time and the after-clicking-the-button-ready-for-the-next-shot response time when taking a photo on both my Sanyo and Minolta digi cameras. This is why I was defragging this old card in the first place. If you can find the time, experiment with fragmented and defragmented cards for yourself, and I think you will agree.

Thanks for your reply, and I fully understand the points you make. However, I still would not expect a defragmenting application to actually give me more than 100% increase in file fragments after processing, and what about that premature 100% status?

I have just used Defraggler to defragment an SD card. After 5 mins or so of busy processing I now have the same % fragmentation and even more file fragments than before, up from 26 to 72. (Screenshot below). http://i212.photobucket.com/albums/cc209/viridens/defraggler1.jpg I realise that there is not much free space on this card, but I did not expect to end up with MORE file fragments. Also, I note that processing continued for a long time after the 'status' percentage claimed it was 100% complete. As a new user I'm not impressed.