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I am trying out a largish SATA solid state disk (120GB Core) Present wisdom is that these SSD's do not need defraging but manufacturer and  Diskeeper say that it will be necessary to consolidate free space. Certainly the free spce gets completely borken up after a few days even though temp directory is set to another conventional SATA drive.
The SSD performance is substantial compared with conventional SATA 10Krpm hard disk and I would love to see  comments in due course

   I do not see why you would not have to defrag.  Fragmentation exists on a solid state drive to the same extent that it exists on a conventional drive.  The difference is that a solid state drive does not have something that has to move to the physical location of the data as a conventional drive does and so fragmentation does not slow down a solid state drive, but the fragmentation is still there.  For all types of drives (conventional and solid state), fragmentation can waste drive space and in extreme cases cause errors.
   To get an idea of what fragmentation is, imagine that you have a table (your drive) and you place a number of blocks flat on it in order for each file you want to add to your drive (the amount of blocks depends on the size of the file).  Some blocks will not be full of data.  To delete a file, you have to remove its blocks.  This leaves empty spaces on the table.  When you add more files, you fill in those empty spaces with the new blocks, but the new file is not the same size as the empty space and so you have to fill in several empty spots scattered across the table.  The more you add and remove files the more scattered (fragmented) the files become over the table.
   Another problem presents itself when you edit a file.  If it gets bigger, the added blocks have to be put somewhere else on the table and not with the other blocks for that file.  If the file gets smaller, blocks are removed leaving empty spaces.
   The Defrag process makes room at the top by moving the blocks there down, and then collects all of the blocks for a file and places them at the top in order.  This puts all of the blocks for one file together and in order.  This process continues until all blocks for each file are together and in order.
   So if you add, remove, or edit files on a drive, it will get fragmented.
   Defragging is highly over-rated especially by the companies that sell defraggers.  I recommend defragging only once a year or so.  More frequent than that and you really do not get much benefit out of it.

I have played with solid-state drives in my last computer build. Everything I've read has indicated that de-fragging SSD drives is detrimental to their performance. (Check the OCZ forums). Partition alignment on the other hand is key. Even Windows 7 which has anticipated SSD drives shuts off defrag for these drives. In short drive indexing, superfetch, pre-fetch and defragmenting are not necessary and detrimental to SSD performance. Check out the following URL by Microsoft: --

http://download.microsoft.com/download/5/E/6/5E66B27B-988B-4F50-AF3A-C2FF1E62180F/COR-T558_WH08.pptx

   The way that defragging is detrimental to SSD performance is that excessive (as in many times a day or daily) defragging can prematurely wear out a SSD.  From what I have read even if it wears out prematurely, it will still last longer than an HDD.  I recommended defragging once a year which is not excessive (one expert recommended once a month).
   One point that is ignored by people who say that a SSD should not be defragged is that fragmentation does happen on a SSD and excessive fragmentation does waste space and can cause problems.
   I came across several reports that defragging a SSD increases the speed even though it may not be noticeable.

Ray, I agree with you regarding your viewpoints on defragging in general. However I have found that different defragging programs use different layouts based on system files, frequency of use etc. I suspect that there could be certain layouts that could be detrimental for SSD's. Furthermore, SSD's have an extraordinarily fast read rate but a surprising slow write rate and the relative impact of defragging would be minimal. I actually found a deterioration on my SSD after defragging.

Thanks Ray and others above for the comments.  Now with two weeks experience of the SSD I conclude I need to check free space because it gets very broken up and this slows downloads so I use Perfect Disk 5 set for defrag\consolidate freespace and triggerd if fragmentation is moren than 2%. In practice it has run twice in two weeks.
Ohterwise the performace is much  better than my WD SATA's. Write speed IS slower so I download very large files for installation to a my WD SATA Raptor disk which stores my installtain files and Acronis Image backups and run them first from there.

I wouldn't take ANYTHING that Microsoft says to the bank.

onemaddude

I have been using a Core 120GB SSD as my C drive for about a year. It is not true that it never needs derfaging because the free space get very broken up and the native slow write speed slows to a crawl.
To minimise this I have moved the temp and internetfiles folders to my main data drive (Drive #2 - WDC WD1500ADFD-00NLR5 (139 GB). I defrag once a week byrebooting from the data drive and using Perfect Disk 10 to defrag the system files an thne run the windows native defrag all this takes baout ten minutes. The I reboot back into the SSD as drive C.
BTW I found Perfect Disk 10 no good for consolidating free space.
John
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