The WD My Passport Slim is a great example of
a slim, fast USB 3.0 HDD

Tech Explainer

Solid state drives perform best when they are relatively empty. This is because the available blocks are a source of "clean" blocks to write to. As the SSD fills up with data, the number of empty blocks available for use drops. If you completely fill an SSD, there won't be any free blocks to use, forcing the drive to erase each and every block before it can be reused, which cripples its performance. That's why SSDs all reserve a portion of their flash memory cells, a technique known as over-provisioning.

Over-provisioning is important as it increases performance by providing pre-erased blocks ready for use, even with the drive is completely filled up. However, this is only temporary as "dirty" blocks quickly accumulate as they get used and discarded. This is a problem with cheaper SSDs because they tend to have less over-provisioning than more expensive drives, due to cost reasons.

This is where the Trim command and automatic garbage collection feature in newer SSDs come in. Trim helps the SSD's automatic garbage collection feature identify and clear "dirty" blocks so they can be reused as clean blocks. Unfortunately, garbage collection can only run when the SSD is idle, so if there is high and persistent activity, garbage collection may not kick in often enough to clear the dirty blocks.

That's why it is important to have as large a buffer of free blocks as possible, and the best way to do that is to keep the SSD as empty as possible.

This SSD is so fragmented, but who cares???

Tech Explainer

Spatial fragmentation of data has no effect on SSD performance - fragmented bits of data are accessed just as quickly as nicely packed blocks, so it is pointless to "defragment" the data blocks in the traditional sense. In fact, defragmenting a solid state drive will rapidly exhaust the drive's supply of clean blocks, resulting in drastically poorer performance right after defragmentation.

Even worse, defragmenting a solid state drive will also reduce its flash memory cells' lifespan by putting them under additional wear and tear. This is a very big problem for consumer-grade SSDs as they use MLC flash memory, which generally last about 5,000 program/erase cycles. In fact, their lifespan is expected to worsen as their fabrication process gets smaller.

Tech Explainer

One of the methods that people in the law enforcement / NSA / high-tech Mafia can use to access your confidential data is to inspect the contents of the paging file. This is because Microsoft Windows' virtual memory architecture automatically maps out idle memory pages to a paging file.

Even if you use encryption to protect sensitive data on the hard disk drive, the encryption key (and any decrypted data that you are accessing) would be stored in the computer's memory. Windows will automatically map out some of these data to the paging file, which remains unencrypted even when Windows shuts down.

That's why those who are worried about this kind of attack would usually use the hidden Windows feature "ClearPageFileAtShutdown" to automatically clear the paging file when Windows shuts down.

However, this is not a foolproof method because when the option is enabled, Windows will only fill inactive pages with zeros. Active pages cannot be filled with zeros because they may be used by the system or other active processes.

If you are truly worried about security, you should boot Windows off a fully-encrypted drive. Then you needn't worry about your sensitive data remaining unencrypted in the paging file.