The Toshiba XG5 (1TB) SSD Review

Random Read Performance

Our first test of random read performance uses very short bursts of operations issued one at a time with no queuing. The drives are given enough idle time between bursts to yield an overall duty cycle of 20%, so thermal throttling is impossible. Each burst consists of a total of 32MB of 4kB random reads, from a 16GB span of the disk. The total data read is 1GB.

The Toshiba XG5 is tied for the position of fastest TLC SSD, sharing that position with the WD Black. The Samsung 960 EVO is about 11% slower, and all of the MLC drives are faster—over 50% faster in the case of Samsung's 960 PRO.

Our sustained random read performance is similar to the random read test from our 2015 test suite: queue depths from 1 to 32 are tested, and the average performance and power efficiency across QD1, QD2 and QD4 are reported as the primary scores. Each queue depth is tested for one minute or 32GB of data transferred, whichever is shorter. After each queue depth is tested, the drive is given up to one minute to cool off so that the higher queue depths are unlikely to be affected by accumulated heat build-up. The individual read operations are again 4kB, and cover a 64GB span of the drive.

When slightly higher queue depths and longer run times come into the picture, the XG5's random read performance looks worse. The XG5 ends up second from last place among PCIe SSDs, with both the WD Black and the Samsung 960 EVO leaping ahead of the XG5.

In spite of relatively poor random read performance, the XG5 continues to deliver great power efficiency that is clearly better than any previous TLC PCIe SSD, including the 960 EVO.

Toshiba XG5 1TBIntel SSD 600p 512GBSamsung 950 PRO 512GBSamsung 960 EVO 1TBSamsung 960 PRO 2TBPatriot Hellfire 480GBOCZ RD400 1TBWestern Digital WD Black 512GBIntel SSD 750 1.2TBPlextor M8PeY 512GB

At every queue depth of the sustained random read test, the Toshiba XG5 uses less power than any competing NVMe SSDs, and it's the only one in this batch to stay under 3W for the whole test. Most of those competitors can ramp up performance faster as the queue depth increases, but the XG5's scaling difficulties aren't very serious.

Random Write Performance

Our test of random write burst performance is structured similarly to the random read burst test, but each burst is only 4MB and the total test length is 128MB. The 4kB random write operations are distributed over a 16GB span of the drive, and the operations are issued one at a time with no queuing.

The Toshiba XG5's QD1 random write performance is about average for NVMe SSDs; only the Intel SSD 750 with its enterprise heritage is a significant outlier.

As with the sustained random read test, our sustained 4kB random write test runs for up to one minute or 32GB per queue depth, covering a 64GB span of the drive and giving the drive up to 1 minute of idle time between queue depths to allow for write caches to be flushed and for the drive to cool down.

The Toshiba XG5's sustained random write performance is far lower than the Samsung 960s or the Intel 750, but the XG5 is still about average for a NVMe SSD even when MLC SSDs are included. The Intel 600p and WD Black offer barely half the random write throughput of the XG5.

The XG5's power efficiency is a close second behind the Samsung 960 PRO, and clearly ahead of the 960 EVO. The XG5's efficiency is three times higher than the TLC-based Intel 600p or WD Black.

Toshiba XG5 1TBIntel SSD 600p 512GBSamsung 950 PRO 512GBSamsung 960 EVO 1TBSamsung 960 PRO 2TBPatriot Hellfire 480GBOCZ RD400 1TBWestern Digital WD Black 512GBIntel SSD 750 1.2TBPlextor M8PeY 512GB

The Toshiba XG5's random write performance flattens out at QD8, which is around where most of the high-performing drives saturate. Unfortunately, the performance of the XG5 when it reaches its limit is nothing remarkable. The XG5's power consumption does remain by far the lowest even across the entire test, though its efficiency is not always superior to the Samsung 960 PRO.