Random Read/Write Speed

The four corners of SSD performance are as follows: random read, random write, sequential read and sequential write speed. Random accesses are generally small in size, while sequential accesses tend to be larger and thus we have the four Iometer tests we use in all of our reviews.

Our first test writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random access that you'd see on an OS drive (even this is more stressful than a normal desktop user would see). We perform three concurrent IOs and run the test for 3 minutes. The results reported are in average MB/s over the entire time.

Desktop Iometer - 4KB Random Write (4K Aligned) - 8GB LBA Space

Our enterprise look at the P3700 focused on steady state 4KB random write performance, but surprisingly enough our short burst/8GB LBA space testing puts the P3700 at a very similar performance level. Here the P3700 is more than twice as fast as the closest SATA competitor, which is amazing despite the low queue depth of our test. I also included the old X25-M G2 to show just how far we've come - the P3700 is nearly 15x the speed of Intel's first generation MLC SSD controller.

Desktop Iometer - 4KB Random Write (8GB LBA Space QD=32)

At a higher queue depth the Z-Drive R4 is able to catch up to the P3700, but being able to deliver excellent random IO performance even at low queue depths is a staple of a good client drive.

Desktop Iometer - 4KB Random Read (4K Aligned)

Random read performance is better than anything else here, but there's a limit to how much parallelism you can extract from a low queue depth random read workload.

Sequential Read/Write Speed

To measure sequential performance we run a 1 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. The results reported are in average MB/s over the entire test length.

Desktop Iometer - 128KB Sequential Read (4K Aligned)

Once again we see the P3700 does extremely well at low queue depths, here its sequential read performance is substantially better than anything else.

Desktop Iometer - 128KB Sequential Write (4K Aligned)

Sequential writes are even more impressive. We typically never see this sort of performance at a queue depth of 1. The P3700's 18-channel controller and firmware do a good job of splitting up write requests across as many parallel die as possible. Once again comparing the P3700 to the old X25-M G2 we see 15x the performance in 6 years.

AS-SSD Incompressible Sequential Read/Write Performance

The AS-SSD sequential benchmark uses incompressible data for all of its transfers. The result is a pretty big reduction in sequential write speed on SandForce based controllers. At a higher queue depth the P3700's performance scales even further. It used to only be possible to see these numbers on PCIe SSDs that leveraged multiple controllers.

Incompressible Sequential Read Performance - AS-SSD

Incompressible Sequential Write Performance - AS-SSD

AnandTech Storage Bench 2013 & 2011 Performance vs. Transfer Size
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