TRIM Performance:

While SSD's offer many benefits, there are some downsides to using flash memory. One of the biggest issues people run into is performance degradation. Over time, an SSD will run out of fresh blocks and will have to write over data the file system has marked as deleted. This procedure is very complicated and can slow an SSD's write speeds considerably.

To fix this problem, most manufacturers have added TRIM support to their SSDs. The TRIM command allows an operating system, such as Windows 7, to tell an SSD which data blocks are no longer in use. Using this information, the drive pro-actively erases these blocks and adds them to the free block pool.

To test the MX500's TRIM and garbage collection functions, I first put the drive in a "dirty" state. I used Iometer to fill 80% of the drive and then ran a random write test for 30 minutes. This had little impact on the MX500's read speed. However, its average writing speed dropped to 81.36 MB/s.

Crucial MX500 - Dirty

To see how well the MX500 could recover, I let the computer sit for about 30 minutes and then reran the test. The drive wasn't able to reach the factory fresh performance shown in our earlier tests. However, its sequential write speed jumped up to 299.59 MB/s.

Crucial MX500 - After TRIM

Lastly, I used Parted Magic to perform a secure erase on the MX500. With the drive wiped clean, it had average read and write speeds of 526.30 MB/s and 459.96 MB/s, respectively.

Crucial MX500 - Secure Erased

Final Thoughts:

If you read our review of Crucial's 1TB MX500 SSD, you already knew that it's one of the better mainstream drives on the market today. The MX500 combines Silicon Motion's SM2258 controller with Micron's new 64-layer 3D TLC NAND to deliver good performance, enhanced features and a high level of endurance at a competitive price. Despite it having half the NAND flash and cache as the 1TB version, the 500GB MX500 performed very well in our tests. The drive was able to read at speeds as high as 561 MB/s and write in excess of 501 MB/s. It also did very well in our random write tests, producing more than 77,000 IOPS at low queue depths.

Fast read and write speeds aren't the only things the MX500 has to offer. Along with thermal and power loss protection, TRIM support and active garbage collection, the drive features AES 256-bit full disk encryption and is compatible with both the TCG Opal and IEEE 1667 specifications. The MX500 also uses Dynamic Write Acceleration to enable faster saves and file transfers, and technologies like Data Defense and Redundant Array of Independent NAND (RAIN) to protect data at the component level and prevent it from becoming corrupted. Last, but not least, the MX500 supports the SATA Device Sleep (DEVSLP) standard which extends the battery life of a device by reducing the drive's power consumption when it's not in use.

The Crucial MX500 is available now in 250GB, 500GB, 1TB and 2TB capacities. Prices on currently range from $75 up to $500, with the 500GB version reviewed here retailing for about $125.


  • Available in 250GB, 500GB, 1TB and 2TB capacities
  • Silicon Motion SM2258 controller
  • Micron 64-layer 3D TLC NAND
  • Good sequential and random read and write performance
  • Dynamic Write Acceleration, Data Defense and RAIN technologies
  • AES 256-bit full disk encryption
  • TCG Opal and IEEE 1667 compliant
  • DEVSLP power mode
  • Supports TRIM, SMART and active garbage collection
  • Thermal and power loss protection
  • Ultra-slim form factor
  • Works with Crucial's Storage Executive software
  • Includes 9.5mm spacer and data migration software
  • 5 year warranty
  • Reasonably priced


  • Write speed drops when SLC cache is full

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