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 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 840 PRO's read speed. However, its average writing speed dropped to a mere 77.5 MB/s.
Samsung SSD 850 PRO 256GB - Dirty
To see how well the 850 PRO could recover, I let the computer sit for about 15 minutes and then reran the test. Looking at the screenshot below, you can see that the drive's average writing speed jumped back up to 418.0 MB/s.
Samsung SSD 850 PRO 256GB - After Trim
Lastly, I used Samsung's SSD Magician software to perform a secure erase of the 850 PRO. With the drive wiped clean, it had average read and write speeds of 435.9 MB/s and 419.7 MB/s, respectively.
Samsung SSD 850 PRO 256GB - Secure Erase
Final Thoughts:
The Samsung 850 PRO is one of, if not the, best consumer-oriented SSDs currently available. Designed and built entirely in-house, this ultra-slim, high-capacity drive combines Samsung's triple-core MEX controller with their second generation, 32-layer 3D V-NAND flash to deliver some of the best all around performance we've seen. In our sequential read and write tests, the 256GB version of the 850 PRO was able to read at speeds as high as 564 MB/s and write at speeds in excess of 493 MB/s. The drive also took the top spot in our random write tests, producing more than 86,000 IOPS at low queue depths.
The 850 PRO performed even better when Samsung's RAPID technology was enabled. The results varied a lot from one benchmark to another, but even on the low end the drive's sequential read and write speeds increased by 65 MB/s. RAPID mode also had a big impact on the drive's random write performance. When tested with Iometer, the 850 PRO's random write speed increased by more than 54 MB/s, giving it the ability to deliver more than 100,000 IOPS at low queue depths.
Impressive performance isn't the only thing the 850 PRO has to offer either. To keep your data safe, the drive features AES 256-bit full disk encryption and is compatible with both the TCG Opal and IEEE 1667 specifications. The 850 PRO also 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. Last, but not least, the 850 PRO is covered by a 10 year warranty.
The 850 PRO is available now in 128GB, 256GB, 512GB and 1TB capacities. Prices on Amazon.com and Pricegrabber currently range from $130 up to $700, with the 256GB version reviewed here going for about $200.
Highs:
- Equipped with 3D V-NAND
- Available in 128GB, 256GB, 512GB and 1TB 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
- Large SDRAM cache
- Supports TRIM, garbage collection and wear leveling
- Features RAPID mode
- AES 256-bit full disk encryption
- TCG Opal and IEEE 1667 compliant
- Includes SSD Magician software and Data Migration Tool
- 10 year warranty
Lows:
- RAPID mode is Windows only
- Pricey
