I've SSD drive hooked on Mac via Firewire800 (could also be USB3). Will the drive wear out quickly due to fact that TRIM command cannot be used on FW800 (same for USB3)? SSD Primer tells that if/when operating system utilizes space for already deleted file will SSD drive's Garbage Collection routine understand that this particular can be collected on next GC run.

What about details? If I used to have e.g. 1 GB file which I deleted and now OS wants write 1 kb(!) file to starting point of previous 1 GB file what happens? Will all former space of 1 GB marked ready to be collected or just only tiny part from start (its only 1 kb file)? I suppose that only that much LBAs as it is needed for 1 kb and rest (huge amount) remaining as "space used" for SSD.

What about future? OS continues to write something here and something there but is there any proof that my SSD will survive? SSDs internal space usage can grow cumulatively on and on if facing bad luck it can some day remain as "all space is used, cannot operate anymore"? This all comes to that SSD does not know anything about filesystem.

If future is that scary how manufactures are trying to handle situation since there a lot of SSD external products available on market? (Those via Thunderbolt connection can understand TRIM command if used)

Edited: I'm utilizing only half of drive full capacity (seeing that from filesystem point of view, don't know SSD internal space utilization as my above writing tells).

  • You have to understand your SSD has a limited number of writes. TRIM is a mechanic to address that fact. If your unable to use TRIM then the end result more writes are performed the otherwise would have happen on a single cell. This means the lifespan of the product will be affected. By how much cannot be predicted. – Ramhound Feb 8 '14 at 16:55

The short answer is that your SSD may fail sooner than if the TRIM command was supported, but not by such a significant margin that you should worry. Drive cell technology (SLC, MLC, or TLC) has a far greater impact on drive life.

You will see a small decrease in write speeds (because when the controller determines that it needs to overwrite a certain block it must first, read, erase, and then write vice just writing, but unless you're looking for ultra speeds this shouldn't hurt you too bad.

  • That entirely depends on how the drive is utilized. If there are a lot of writes and deletes happening (i.e. in an enterprise setting with MLC/TLC) then doing without TRIM might very quickly degrade the flash memory. – Maarten Bodewes Jul 2 '15 at 16:43

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