10-19-2014, 02:59 AM
sekker wrote:
OWC includes garbage collection in its firmware, as do many other name-brand SSD manufacturers.
Not sure this is a big deal unless you have an older SSD.
Garbage collection is not TRIM.
http://www.tomshardware.com/forum/279412...dead-horse
...4. TRIM is beneficial to all SSDs regardless of what kind of garbage collection is used. I talk about how TRIM came into existence and why it is necessary in my blog http://blog.lsi.com/did-you-know-hdds-do-not-have-a-del... . The TRIM command is sent by the OS to the SSD to identify what pages of data can be ignored during garbage collection. The SSD cannot tell what files have been deleted until the OS uses the same sectors to store new files, but by that time the SSD has already wasted cycles by garbage collecting data that was invalid, but known to the SSD.
5. TRIM will benefit all SSDs in some way. Some will benefit more than others depending upon their situation.
...
9. Garbage collection without TRIM will always be moving all invalid data during the GC process acting like the SSD is operating at full capacity. Only the TRIM command can identify the invalid data and improve performance.
10. A 128GB SSD with TRIM and only 64GB of user data will operate like an SSD with 64GB of over provisioning, meaning it will operate at its fastest level.
11. TRIM identifies what the OS no longer wants to save, but nothing changes on the SSD until the GC process actually recycles that block of pages and skips the TRIMed invalid data.
12. GC is not a replacement for TRIM regardless of foreground or background type. TRIM can only make the GC process more efficient and lower the write amplification...
...the performance gain after TRIM comes from two places. First, TRIM tells the SSD to stop tracking invalid data during garbage collection. This speeds up the garbage collection process. Second, the pages of data that are now freed up will automatically turn into "dynamic" over provisioning. Since larger amounts of over provisioning will improve SSD performance, this increased dynamic over provisioning helps as well.