Random Performance – Iometer (IOPS/latency), YAPT (random)

We are trying something different here. Folks tend to not like to click through pages and pages of benchmarks, so I'm going to weed out those that show little to no delta across different units (PCMark). I'm also going to group results performance trait tested. Here are the random access results:


Iometer is an I/O subsystem measurement and characterization tool for single and clustered systems. It was originally developed by the Intel Corporation and announced at the Intel Developers Forum (IDF) on February 17, 1998 – since then it got wide spread within the industry. Intel later discontinued work on Iometer and passed it onto the Open Source Development Lab (OSDL). In November 2001, code was dropped on SourceForge.net. Since the relaunch in February 2003, the project is driven by an international group of individuals who are continuously improving, porting and extend the product.

Iometer – IOPS

The 120GB 750 EVO comes on strong but runs out of steam at QD=32 in our file server test, and carries through using TLC for the rest of the sequence, resulting in relatively low figures on the database and workstations runs. Bear in mind that such high QD sweeps are a bit extreme for consumer SSDs, and we are introducing new testing (on the next page) that focuses on consumer appropriate workloads and lower queue depths. Despite the higher demands of this testing, the 250GB capacity of the 750 EVO fared reasonably well.

Iometer – Average Transaction Time

For SSD reviews, HDD results are removed as they throw the scale too far to tell any meaningful difference in the results. Queue depth has been reduced to 8 to further clarify the results (especially as typical consumer workloads rarely exceed QD=8). Some notes for interpreting results:

  • Times measured at QD=1 can double as a value of seek time (in HDD terms, that is).
  • A 'flatter' line means that drive will scale better and ramp up its IOPS when hit with multiple requests simultaneously, especially if that line falls lower than competing units.

These are average latencies included for completeness. More relevant Latency Percentile results are on the next page.

YAPT (random)

YAPT (yet another performance test) is a benchmark recommended by a pair of drive manufacturers and was incredibly difficult to locate as it hasn't been updated or used in quite some time.  That doesn't make it irrelevant by any means though, as the benchmark is quite useful.  It creates a test file of about 100 MB in size and runs both random and sequential read and write tests with it while changing the data I/O size in the process.  The misaligned nature of this test exposes the read-modify-write performance of SSDs and Advanced Format HDDs.

YAPT is a 'misaligned' test, in that it does not adhere to 4k boundaries. This makes some SSDs flinch a bit, and appear to cause the smallest 750 EVO to blow through its cache more quickly than expected. Remember that this is a bit of a torture test and is not necessarily what would be seen in simple consumer-type of use. It's also a safe assumption that these newer Samsung firmwares are heavily optimized around 4k operations (accepted standard for current file systems), so this test may hurt a bit more than normal.

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