This is why recovery software like Hard Disk Warrior is able to recover files that have been ‘erased’. Instead, the OS simply marks the blocks as being available and stores that information in a directory file. The OS does not typically erase the storage blocks that were previously inhabited by the file. Every file system has its own way of doing things, but generally speaking, when you delete a file, that file is not really gone.

In order to understand why SSDs get slower over time, it’s important to know how file systems work. With proper maintenance, the speed of an SSD can be preserved. This is exactly the thing that SSD garbage collection is designed to prevent. We all know SSDs are initially very fast but, we are finding out that they get slower over time, especially as the drive begins to fill up. At its core, SSD garbage collection is an automated process that is designed to improve performance. It’s more like getting rid of empty boxes of things you’ve already thrown away. It’s somewhat of a misnomer since garbage collection has nothing to do with removing files that are no longer needed. Just like taking out the trash is a necessary task in maintaining your home, garbage collection is also a type of SSD maintenance. Fortunately, there are things you can do that can prevent this from happening and help you maintain the speedy nature of your SSDs. You'll get that 78GB drive space back - in a day or two after the installation is complete.The rumblings online and in certain IT circles have proven to be true: SSD speeds can slow down over time. The reason so much space is required is because TRIM and GC will need time to prepare the SSD to accept new data after deletion. This is because Native Access downloads, expands, installs then deletes each library in the process.

I was reading that, to do a complete install of Komplete Ultimate Collectors 13, you need at least 78 GB available on your system drive if you plan to install it to an attached drive. With TRIM enabled, it might take as little as 24–28 hours. If you erase a nearly full 2TB sample drive and try to rewrite to it, without TRIM, it might take over 48 hours before you have access to the full capacity. Garbage Collection is a utility contained in the drive's firmware and is a lot slower.

TRIM is the OS communicating with the SSD as it tries to ready the cells for new data. When it could be enabled easily in OS 10.10.4, it was interesting to read all the walking back they had to do. A long time ago, OWC spread the misinformation that TRIM wasn't necessary.

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