The Intel SSD 600p (512GB) Review

Performance Consistency

Our performance consistency test explores the extent to which a drive can reliably sustain performance during a long-duration random write test. Specifications for consumer drives typically list peak performance numbers only attainable in ideal conditions. The performance in a worst-case scenario can be drastically different as over the course of a long test drives can run out of spare area, have to start performing garbage collection, and sometimes even reach power or thermal limits.

In addition to an overall decline in performance, a long test can show patterns in how performance varies on shorter timescales. Some drives will exhibit very little variance in performance from second to second, while others will show massive drops in performance during each garbage collection cycle but otherwise maintain good performance, and others show constantly wide variance. If a drive periodically slows to hard drive levels of performance, it may feel slow to use even if its overall average performance is very high.

To maximally stress the drive's controller and force it to perform garbage collection and wear leveling, this test conducts 4kB random writes with a queue depth of 32. The drive is filled before the start of the test, and the test duration is one hour. Any spare area will be exhausted early in the test and by the end of the hour even the largest drives with the most overprovisioning will have reached a steady state. We use the last 400 seconds of the test to score the drive both on steady-state average writes per second and on its performance divided by the standard deviation.

The Intel 600p's steady state random write performance is reasonably fast, especially for a TLC SSD. The 600p is faster than all of the SATA SSDs in this collection. The Intel 750 and Samsung 960s are in an entirely different league, but the OCZ RD400 is only slightly ahead of the 600p.

Despite a decently high average performance, the 600p has a very low consistency score, indicating that even after reaching steady state, the performance varies widely and the average does not tell the whole story.

Default	Intel SSD 600p 512GBIntel SSD 600p 512GB (PCIe 2x2)ADATA Premier SP550 480GBCrucial MX300 525GBIntel SSD 540s 480GBOCZ RD400 512GB (M.2)OCZ RD400A 512GBOCZ VX500 512GBPNY CS1311 480GBPNY CS2211 480GBSamsung 850 EVO 500GBSamsung 850 Pro 512GBSamsung 950 Pro 512GBSamsung 960 EVO 1TBSamsung 960 Pro 2TBCorsair Neutron XT 480GBCrucial BX100 500GBCrucial MX100 512GBOCZ Trion 100 240GBOCZ Trion 100 480GBOCZ Trion 100 960GBOCZ Vector 180 480GBOCZ Vector 180 960GBIntel SSD 750 1.2TB (PCIe 3.0 x4 - NVMe)Samsung SM951 512GB (PCIe 3.0 x4 - AHCI)Samsung XP941 512GB (PCIe 2.0 x4 - AHCI)
25% Over-Provisioning	ADATA Premier SP550 480GBCrucial MX300 525GBIntel SSD 540s 480GBIntel SSD 600p 512GBIntel SSD 600p 512GB (PCIe 2x2)OCZ RD400 512GB (M.2)OCZ RD400A 512GBOCZ VX500 512GBPNY CS1311 480GBPNY CS2211 480GBSamsung 850 EVO 500GBSamsung 850 Pro 512GBSamsung 950 Pro 512GBSamsung 960 EVO 1TBSamsung 960 Pro 2TBCorsair Neutron XT 480GBCrucial BX100 500GBCrucial MX100 512GBOCZ Trion 100 960GBOCZ Vector 180 480GBSanDisk Ultra II 240GB

Very early in the test, the 600p begins showing cyclic drops in performance due to garbage collection. Several minutes into the hour-long test, the drive runs out of spare area and reaches steady state.

Default	Intel SSD 600p 512GBIntel SSD 600p 512GB (PCIe 2x2)ADATA Premier SP550 480GBCrucial MX300 525GBIntel SSD 540s 480GBOCZ RD400 512GB (M.2)OCZ RD400A 512GBOCZ VX500 512GBPNY CS1311 480GBPNY CS2211 480GBSamsung 850 EVO 500GBSamsung 850 Pro 512GBSamsung 950 Pro 512GBSamsung 960 EVO 1TBSamsung 960 Pro 2TBCorsair Neutron XT 480GBCrucial BX100 500GBCrucial MX100 512GBOCZ Trion 100 240GBOCZ Trion 100 480GBOCZ Trion 100 960GBOCZ Vector 180 480GBOCZ Vector 180 960GBIntel SSD 750 1.2TB (PCIe 3.0 x4 - NVMe)Samsung SM951 512GB (PCIe 3.0 x4 - AHCI)Samsung XP941 512GB (PCIe 2.0 x4 - AHCI)
25% Over-Provisioning	ADATA Premier SP550 480GBCrucial MX300 525GBIntel SSD 540s 480GBIntel SSD 600p 512GBIntel SSD 600p 512GB (PCIe 2x2)OCZ RD400 512GB (M.2)OCZ RD400A 512GBOCZ VX500 512GBPNY CS1311 480GBPNY CS2211 480GBSamsung 850 EVO 500GBSamsung 850 Pro 512GBSamsung 950 Pro 512GBSamsung 960 EVO 1TBSamsung 960 Pro 2TBCorsair Neutron XT 480GBCrucial BX100 500GBCrucial MX100 512GBOCZ Trion 100 960GBOCZ Vector 180 480GBSanDisk Ultra II 240GB

In its steady state, the 600p spends most of the time tracing out a sawtooth curve of performance that has a reasonable average but is constantly dropping down to very low performance levels. Oddly, there are also brief moments of unhindered performance where the drive spikes to exceptionally high performance of up to 100k IOPS, but these are short and infrequent enough to have little impact on the average performance. It would appear that the 600p occasionally frees up some SLC cache, which then immediately gets used up and kicks off another round of garbage collection.

With extra overprovisioning, the 600p's garbage collection cycles don't drag performance down as far, making the periodicity less obvious.