TRIM Performance:
While SSDs 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 SSD 840 Pro's TRIM function, I first put the drive in a "dirty" state. I used Iometer to fill the entire drive and then ran a random write test for 30 minutes. This had little impact on the SSD 840 Pro's read speed. However, its average writing speed dropped to a mere 58.6 MB/s.
Samsung SSD 840 Pro 512GB - Dirty
To see how well the SSD 840 Pro could recover, I let the computer sit for about an hour and a half and then reran the test. Looking at the screenshot below, you can see that the drive's average writing speed jumped back up to 398.4 MB/s.
Samsung SSD 840 Pro 512GB - After Trim
Lastly, I used Samsung's SSD Magician software to perform a secure erase of the SSD 840 Pro. With the drive wiped clean, it had average read and write speeds of 442.1 MB/s and 399.6 MB/s, respectively.
Samsung SSD 840 Pro 512GB - Secure Erase
Final Thoughts:
This is not the first time we've looked at Samsung's 840 Pro Series SSD and even now, months after its introduction, it continues to be one of the best consumer-grade SSDs on the market. Designed and built entirely in-house, this attractive, ultra-slim SSD combines Samsung's triple-core MDX controller with their own Toggle DDR2 NAND flash memory to deliver some of the best all around performance we've seen. In our sequential read and write tests, the 512GB version of the SSD 840 Pro was able to read at speeds as high as 560 MB/s and write at speeds in excess of 500 MB/s. The drive also did very well in our random write tests, producing more than 86,000 IOPS at low queue depths. Moreover, it performed equally well with compressible and incompressible data and was able to sustain these speeds, even after intensive use.
The SSD 840 Pro is available now in 128GB, 256GB and 512GB capacities. Prices on Amazon.com currently range from $133 up to $469 for the 512GB version reviewed here.
Highs:
- Available in 128GB, 256GB and 512GB capacities
- Excellent sequential read and write speeds
- Very good random read and write performance
- Performs equally well with compressible and incompressible data
- Good looking, ultra-slim design
- SATA 6Gb/s interface
- Toggle DDR MLC NAND flash
- Large SDRAM cache
- Supports TRIM, garbage collection and wear leveling
- AES 256-bit full disk encryption
- Includes SSD Magician software and Data Migration Tool
- 5 year warranty
Lows:
- Does not include an adapter bracket or cables
- Pricey
