Disk Response Time
In this test IOMeter is sending a stream of requests to read and write 512-byte data blocks with a request queue depth of 1 for 10 minutes. The total amount of requests processed by the drive is much more than its cache buffer, so we get a sustained response time that doesn’t depend on the amount of cache memory the drive has.
Although the SSDs differ greatly in their response time, all of them are far more responsive than HDDs because of the lack of moving parts. An HDD has to move the heads to the necessary track and wait for the necessary sector to come up on the rotating platter, so even the best of today’s HDDs (15,000 rotations per minute!) cannot have a response time smaller than 2 milliseconds. SSDs deliver far better results.
Within this device category, Intel’s SSD has the smallest response while the pair of Kingston’s SSDs have the highest response time.
The numbers change dramatically when we switch to writing. Most of the SSDs – the Intel and all of the Indilinx-based models – deliver very good results, obviously thanks to buffer memory and effective firmware algorithms. The Super Talent MasterDrive SX and the Kingston V+ series are not so good. The former seems to have a large buffer but cannot effectively access flash memory for writing. Toshiba’s new controller in the V+ drive is impressive at writing, especially in comparison with the V series models which have the awfully high write response time as is typical of the JMicron 602B controller. By the way, take note that the 128GB model is almost two times as slow as its 64GB cousin within Kingston’s V series.