Samsung 840 EVO 250GB SSD Review

HD Tune Pro

Version and / or Patch Used: 4.00

Developer Homepage: http://www.efdsoftware.com

Product Homepage: http://www.hdtune.com

HD Tune is a Hard Disk utility which has the following functions:

Benchmark: measures the performance

Info: shows detailed information

Health: checks the health status by using SMART

Error Scan: scans the surface for errors

Temperature display

HD Tune Pro gives us accurate read, write and access time results and for the last couple of years has gained popularity amongst reviewers. It is now considered a must have application for storage device testing.

In the charts today, we'll have the 840 EVO with and without RAPID Mode. Some of the charts will be a little wonky since RAPID elevates the performance so much in some tests. Unlike other cache solution like NVELO's Dataplex or Intel's built-in chipset + SSD, we didn't need to run the tests twice to see a performance increase. The results shown are from our standard, every day, every product, performance test suite.

In the first test, reading sequential data across the span of the drive, the 840 EVO does well. RAPID increases the minimum transfer speed, but doesn't take the performance to the next level.

The 840 EVO has a couple of levels of cache and below we'll show them plotted on a chart. The TLC area of the drive actually only writes at around 250MB/s, but the SLC mode area writes at roughly 440MB/s. In this test, RAPID writes right around 1GB/s. This test uses 64KB blocks.

HD Tach - Sequential Write Performance after Random Writes

We're using RAPID in this plot and we can see the different stages of write performance. RAPID starts at the left and then trails off. It's important to note that the RAPID performance isn't just a one shot, 1GB of space and quit boost. This test uses 128KB blocks sequentially. After RAPID you can see the SLC tier and finally the TLC tier. At the end of the TLC tier you can see the drive freaking out. That's the latency involved with losing spare area mixed with aggressive garbage collection. It's like in Star Wars, in the garbage chute when the walls are closing in. That's the same level of panic the controller is going into.

It's important to understand that under regular use no one writes the full span of their SSD, at least not all at once and not in just a few minutes. The testing tools on this page came well before SSDs hit the market.