The Intel SSD 600p (512GB) Review

Final Words

The Intel SSD 600p is intended to be the most mainstream PCIe SSD yet without the hefty price premium that previous PCIe SSDs have carried relative to SATA SSDs. Its performance needs to be evaluated in the context of its price and intended market, both of which are quite different from that of products like the Samsung 960 Pro and 960 EVO. The more appropriate standard to compare against is the Samsung 850 EVO.

Even with our expectations thus lowered, the Intel SSD 600p fails to measure up. But this isn't a simple case of a budget drive that turns out to be far slower than its specifications would imply. The SSD 600p does offer peak performance that is as high as promised. The trouble is that it only provides that performance in a narrow range of circumstances, and most of our usual benchmarks go far beyond that and show the 600p at its worst.

The biggest problem with the Intel SSD 600p seems to be its implementation of SLC caching. The cache is plenty and its fixed size prevents the drive from performing vastly worse when full, the way the Crucial MX300 and OCZ VX500 suffer. But the 600p sends all writes through the SLC cache even when it is full, which creates extra work for the SSD controller, and the SM2260 can't keep up. Once the SLC cache has been filled, further sustained writes will put the drive through frequent garbage collection cycles to flush part of the SLC cache. While that extra background work is proceeding, the 600p slows to a crawl and peak write latencies can spike to over half a second.

In the early days of the SSD market, many drives and controllers were condemned for seizing up under load. The SSD 600p reminds us of those problems, but it isn't so severely crippled. The SSD 600p is completely unsuitable for a database server, but at its worst is is only as bad as a budget SATA SSD, not a dying hard drive. Ordinary interactive desktop usage provides the SSD 600p plenty of idle time to clean up and the 600p will perform better than any SATA SSD. Even when the 600p is subjected to an unrealistically intense sustained write load, its stutters are very brief and in between it catches up very quickly with bursts of very high performance. In spite of its problems, the SSD 600p managed a steady-state random write speed higher than almost all consumer SATA SSDs.

The Intel SSD 600p would be a bad choice for a user who regularly shuffles around tens of gigabytes of data. On paper however, it offers great performance for light workloads. The problem is that for workloads light enough to never expose the 600p's flaws, even a slower and cheaper SATA SSD is plenty fast and the 600p's advantages would be difficult to feel (bar installation in a smaller form factor). The niche that the SSD 600p is most suited for is also one that doesn't need a faster SSD. The SSD 600p doesn't set any records for price per gigabyte except among NVMe SSDs, and its power efficiency is a problem for mobile users. Taken together, these factors mean that users for whom the SSD 600p would work well will almost always be better served by getting a cheaper and possibly larger SATA SSD if they have the space.

It is possible that the Intel SSD 600p's flaws could be mitigated by different firmware. The SM2260 controller is obviously capable of handling high data rates when it isn't busy unnecessarily shuffling data in and out of the SLC cache. We don't know for sure why Micron chose to cancel the Ballistix TX3 SSD that was due to use SM2260 with 3D MLC, but even if that combination wasn't going to be able to compete in the highest market segment, the controller is certainly capable of going far beyond the performance limits of SATA.

The Intel/Micron 3D TLC NAND is clearly not as fast as Samsung's 3D TLC V-NAND, but the Crucial MX300 has already shown us that the SSD 600p's limitations are not all directly the result of the NAND being too slow. It is unlikely that Intel will overhaul the firmware of the 600p, but it is quite possible that future products will do a better job with this hardware. The first product we tested with Silicon Motion's SM2256 controller was the infamous Crucial BX200, but it was followed up by successors like the ADATA SP550 that proved the SM2256 could make for a good value SSD.

The results of testing the SSD 600p in the motherboard's more limited PCIe 2.0 x2 M.2 slot bring up some interesting questions about the future of low-end NVMe products. For the most part, the effects of the bandwidth limitation on the SSD 600p were barely noticeable. PCIe 3.0 x4 is far faster than necessary to simply be faster than SATA, and supporting an interface that fast has costs in both controller die size and power consumption. The SSD 600p might have been better served by a controller that sacrificed excess host interface bandwidth to allow for a more powerful processor within the same TDP, or to just lower the price a bit further. Even though OEMs are striving to ensure that their M.2 slots can support the fastest SSD, not every drive needs to use all of that bandwidth.