4 KB Random Performance
Toshiba's MK4001GRZB is able to take full advantage of its SAS 6 Gb/s interface in this test, exceeding the performance of its SATA-based competition running at the same data rate. Presented with a queue depth of 32, performance starts to plateau at roughly 95 000 IOPS. The nearest competition is Micron's SLC-based P300, which starts higher than Toshiba's drive at lower queue depths, but falls just short of 60 000 IOPS with 16 outstanding commands or more.
Intel, the indisputable favorite amongst IT professionals shopping for enterprise-class SSDs, has a very driven focus on reliably. So much so, in fact, that its client-oriented drives are being used in certain server-based environments. So, we thought it'd be fitting to include SSD 320 and SSD 520 into our benchmarks for the sake of comparison. Interestingly, the company's SandForce controller-based drive achieves up to 50 000 IOPS using Intel's binned MLC flash. That falls shy of the P300, but it's a substantial improvement over the SSD 320 and more business-class SSD 710. And when we hit the drive with incompressible data, indicated by the light blue line marked Random, performance remains similar. The SandForce controller's reliance on compression for exceptional performance doesn't become a factor until we analyze write speed.
The MK4001GRZB has a rated random write speed of 16 000 IOPS at a queue depth of 16. According to our Iometer testing, that figure applies to all queue depths once the drive hits its steady state. In comparison, Micron's P300 performs much better, as it hits speeds just over 20 000 IOPS.
As an aside, Intel's SSD 520 really struts its stuff in this test thanks to SandForce's second-gen controller. At a queue depth of 64, the desktop-class SSD plateaus at speeds just over 50 000 IOPS.
Once we hit the steady state for 4 KB random I/O, the P300's average response time appears just slightly lower than Toshiba's MK4001GRZB, though the delta is only 25%.
Yet, in the same environment, peak response time measurements actually favor the SLC-based SSD. Going by the numbers, the max response time for the MK4001GRZB is 53.7 ms, which is almost 8x lower than the P300.
Although we don't mean to keep taking the emphasis off enterprise-class storage, we're again surprised by Intel's relatively new SSD 520. Depending on data type, the drive's maximum response time falls between ~125-155 ms. This puts the SSD 520 on par with Intel's SSD 710, and slightly better than its client-oriented SSD 320.