oddly, I was over reading some comments at OWC and found this post from here (
http://blog.macsales.com/11051-to-trim-or-not-to-trim-owc-has-the-answer#comments )
he does make some valid points but I am no expert with regards to this subject and will follow the ssd manufacturers advice (OWC),..
Michael's post below:
Michael
June 27, 2012 at 9:48 am
I contacted Sandforce regarding to Trim or not to Trim – They gave me good insight into their process:
Here is a background on TRIM and GC-
First – they are separate and not to be considered the same!
In flash memory, Garbage Collection (GC) is the process of relocating existing data, deleting stale data, and creating empty blocks for new data
All SSDs have some form of GC – it is not an optional feature
NAND flash cannot directly overwrite a page with data; it has to be first erased
One full block of pages has to be erased, not just one page
GC starts after each page has been written one time
Valid data is consolidated and written into new blocks
Invalid (replaced) data is ignored and gets erased
Wear leveling mainly occurs during GC
The OS tracks what files are present and what logical blocks are holding the files
SSDs do not understand the file structure of an OS; they only track valid data locations reported by the OS
When the OS deletes a file, it marks the file’s space in its logical table as free – It does not tell the drive anything
When the OS writes a new file to the drive, it will eventually write to the previously used spaces in the table
An SSD only knows data is no longer needed when the OS tells it to write to an address that already contains data
How Trim Works -
The OS sends a TRIM command at the point of file deletion
The SSD marks the indicated locations as invalid data
TRIM Features:
► Prevents GC on invalid data
► Increases the free space known to the SSD controller
TRIM Benefits:
► Higher throughput – Faster host write speeds because less time writing for GC
► Improved endurance – Reduced writes to the flash
Lower write amplification – Less data rewritten and more free space is available • TRIM does not generally work behind a RAID environment
Sandforce has a patented technology called Durawrite. I assume that OWC assesses that Durawrite is better than TRIM and makes TRIM obsolete. I don’t agree. Sandforce does not agree, they recommend running Durawrite and TRIM together. (Kent Smith – Sr. Director of Corporate Marketing SandForce)
Please see the linked chart from SandForce. –
https://forums.macrumors.com/attachment.php?attachmentid=345371&d=1340805193
Free Space for GC equals higher performance.
