The Team Group T-Force Cardea (240GB) SSD Review: Grace Under Write Pressure

AnandTech Storage Bench - Light

Our Light storage test has relatively more sequential accesses and lower queue depths than The Destroyer or the Heavy test, and it's by far the shortest test overall. It's based largely on applications that aren't highly dependent on storage performance, so this is a test more of application launch times and file load times. This test can be seen as the sum of all the little delays in daily usage, but with the idle times trimmed to 25ms it takes less than half an hour to run. Details of the Light test can be found here. As with the ATSB Heavy test, this test is run with the drive both freshly erased and empty, and after filling the drive with sequential writes.

On the Light test, the Team T-Force Cardea has a much lower average data rate than the larger Phison E7 drives or any of the other NVMe SSDs in this bunch.

The average and 99th percentile latency scores of the T-Force Cardea are fine when the test is run on an empty drive, but are much worse when the drive is full. The Samsung 960 EVO is also strongly affected by a full drive, but its empty-drive performance is so good that the full-drive scores are still better than any of the Phison E7 drives, especially the T-Force Cardea.

Splitting the average latency into reads and writes reveals that the T-Force Cardea's most acute problem on the Light test is write latency when the drive is full.

The full-drive write latency penalty of the T-Force Cardea is even more apparent when looking at 99th percentile write latency than average write latency. Otherwise, its latency compares favorably against the other Phison E7 drives and is much lower than the SATA drives. The Samsung 960 EVO has a problem with read latency when full, but its write latency stays very good even when full.

The two M.2 Phison E7 SSDs are tied for power consumption, along with the OCZ RD400. The only drives in this bunch that are more power-hungry are the add-in card form factor Phison E7 drives. Samsung's drives are all much more efficient, especially the 850 EVO.