The SanDisk X400 1TB SSD Review

Random Read Performance

The random read test requests 4kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test spans the entire drive, which is filled before the test starts. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

The X400's random read performance is almost as good as the Samsung 850 EVO and much better than the other planar TLC drives. This is a significant accomplishment, as random reads are often the slowest operation for TLC drives and hard to improve with caching.

The X400's mid-range random read performance is achieved with relatively low power consumption, making it surprisingly efficient for a TLC drive.

SanDisk X400 1TBCrucial BX100 1TBCrucial BX200 960GBCrucial MX200 1TBOCZ Trion 100 960GBOCZ Trion 150 960GBOCZ Vector 180 960GBSamsung 850 EVO 1TBSamsung 850 Pro 1TBSanDisk Extreme Pro 960GB

At the highest queue depths the X400 can't quite reach the limits of the fastest drives, but overall the scaling of both performance and power usage are reasonable for a mid-range SATA drive.

Random Write Performance

The random write test writes 4kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test is limited to a 16GB portion of the drive, and the drive is empty save for the 16GB test file. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

The X400's low queue depth random write speeds fall in the middle of the gap between the slowest MLC drive and the rest of the planar TLC drives.

The X400's power consumption is low, but with performance well behind any MLC drive the efficiency is only better than the other planar TLC drives.

SanDisk X400 1TBCrucial BX100 1TBCrucial BX200 960GBCrucial MX200 1TBOCZ Trion 100 960GBOCZ Trion 150 960GBOCZ Vector 180 960GBSamsung 850 EVO 1TBSamsung 850 Pro 1TBSanDisk Extreme Pro 960GB

The SanDisk X400's random write speeds show almost no scaling with increased queue depths, behavior that is typical of low-end TLC drives. The QD1 performance is as good as any SATA drive and while the OCZ Trion 150 hits great speeds at QD16 and QD32, the SanDisk X400 is clearly faster for the more realistic lower queue depths.