Iometer Results

Website: Iometer

Iometer is a powerful open source synthetic benchmarking tool, able to simulate the effects of a wide variety of software loads and circumstances on either individual hard disk drives and complete drive arrays. In the past we've chosen not to include it due to bit-tech's traditional preference towards real world benchmarks. However, to correctly check for drive stutter caused by extremely high random write latencies there aren't a great deal of options, so we've finally decided to include Iometer in our hard disk testing suite.

For our Iometer testing we used a 4GB portion of the drive and subjected it to random read or write commands or both, depending on the test, of 4KB, with three outstanding I/Os to simulate high level multi-tasking. We ran this each test for two minutes, repeating three times to ensure we recorded an accurate result.

As the differences in read and write latencies and speeds can be so pronounced, we've also included tables of information where appropriate, to help make understanding the random read/write performance differences between different SSDs and conventional hard disk drives easier.


Random write speed has been the bane of many solid state drives, with poor speeds inferior to those of conventional hard disk drives leading to disappointing everyday operating system performance. Thankfully the Corsair P256 doesn't suffer from such issues, and while not as fast at random write speeds as either the OCZ Vertex or Intel X25-M, is still more than twice as fast as the nippiest mechanical hard drive.


Random write response time has been one of the real shortcoming of the JMicron based drives such as the OCZ Apex or G.Skill Titan. While they deliver great sequential speeds, random write latencies for those drives are very poor, leading to the now infamous drive stuttering, caused by the long latencies as the drive writes data to a new location. Happily the Corsair P256 is stutter free, with an average write latency of 2.5ms, more than twice as fast as the quickest hard disk drive but notably slower than the OCZ Vertex.


Maximum write latencies cause the most marked effects of drive stuttering, as can be seen by looking at the two JMicron based G.Skill drives poor score. In comparison the Corsair P256 is extremely quick, with a maximum write latency of just 18ms. While this is marginally faster than a 10,000RPM hard disk drive, it is slower than the OCZ Vertex by a wide margin, although when dealing with such fractional amounts of time the real world difference between the two is negligible.