It's another historic day for consumer SSDs. Today Intel begins selling the first consumer NVMe SSD with 4-bit per cell flash technology (QLC).
Like 3-bit per cell (TLC) before it, there is a lot of fear surrounding QLC. Will the technology provide enough write endurance, how long will data last on the memory, and the area that terrifies many the most, how much latency will the extra bit add?
We can't answer some of those questions today, but so far the Intel 660p looks really good. It's not a complete game changer, but it's a helluva lot better than we expected. Intel's 64-layer QLC memory uses a slightly faster IO bus speed compared to 64-layer TLC memory. Intel paired the memory with a Silicon Motion, Inc. (SMI) SM2263 controller that is similar to the SM2262, so the application performance is exceptional.
4-bit per cell from Intel stores 33% more data per die over 3-bit per cell media. The technology enables SSD manufacturers to meet aggressive price points. The 1TB Intel SSD 660p with QLC costs $174 less than the 1TB SSD 760p and moves NVMe into the same price verticals as SATA SSDs shipping today.
Let's look at the numbers first and then dive into how Intel got there with the hardware details and feature set for this series. The 660p comes to market in three capacities, 512GB, 1TB, and 2TB. The 1-Terabit die size is not effective for smaller sizes like 128GB and 256GB, a detail we'll look at later in this review.
The 660p features symmetric for all three sizes. The series offers users up to 1,800 MB/s sequential read and write performance. The random performance reaches as high as 220,000 IOPS, also for both reads and writes.
Intel utilized the lower cost SMI SM2263 for the 660p. The SM2263 is the 4-channel version of the SM2262 (8-channel) used in the SSD 760p.
The Intel 660p with QLC memory delivers 200 MB/s more sequential write performance than the SSD760p with TLC memory. Intel-enabled SMI's Intelligent Dynamic SLC-Caching technology on this series. The technology makes drives like the HP EX920, Adata SX8200, and Mushkin Pilot the gamer's choice for flash-based storage today.
The SLC cache expands and contracts, depending on the amount of data stored on the flash. Intel is the first company to disclose the size of the flash and the incremental shrink as users store more data.
For my personal use, I use the size of a Blu-Ray ISO file, around 50-gigabytes, for the cache size target and a 10-gigabit ethernet network speed, it's around 1,000 MB/s for sequential writes. I want an SSD capable of writing 50GB at close to 1,000 MB/s to personal PC over a network.
The capacity of your SSDs matters. The Intel SSD 660p 2TB surpasses my personal needs all the way up to 75% fill, the amount of data already stored on the drive. That backs down to 65% for the 1TB model and 45% on the 512GB model.
Writes outside of the SLC cache fall to native QLC write speeds. In our 128KB sequential write test on a 1TB 660p, the native QLC write speed is right around 85 MB/s. The performance is right around what we measured with planar TLC technology using a 512GB drive that was popular in 2015. 3D TLC's native write performance after the SLC buffer is considerably faster, around 250 MB/s using the same workload. Most users will never see native QLC speeds under normal workloads unless you transfer large files, like Blu-Ray ISOs.
The SSD 660p is Intel's successor to the 600p. Most companies categorize these at "mainstream NVMe". At one time we called these products entry-level NVMe, but with DRAMless NVMe products coming to market like the Toshiba RC100, there is a clear divide between the two classifications.
The Intel 660p ships with features we rarely see on mainstream NVMe products. The series supports user AES-256 encryption with Pyrite 1.0 and 2.0. The series also comes with a 5-year warranty in a world where most mainstream SSDs only carry a 2- or 3-year warranty.
The series starts out at $99 for the SSD 660p 512GB. The price is less than Samsung's 860 EVO 500GB SATA SSD. The SSD 660p doubles the price to $199, also lower than a similar capacity 860 EVO. We don't have pricing for the SSD 660p 2TB but suspect it will sell between $380 and $400.
Intel covers the series with a full 5-year warranty but this isn't the SSD you want to use to download Torrent files. Endurance is the weak spot right now. Intel has been on the conservative side with TLC and we hope the QLC ratings are also conservative. What makes Intel different from other manufacturers is how the products react to reaching the limits of guaranteed coverage. The Intel consumer SSDs will move into a read only state making booting from the drives impossible. Other company's consumer SSDs will warn users through Windows, but not build a brick wall that limits usability.
Intel gives users 100 TBW for every 512GB. The 1TB 660p includes 200 TBW coverage and the 2TB gives users 400 terabytes of data writes.
The SSD 660p uses a custom SMI SM2263 4-channel controller. The very large die density means the 1TB drive uses just two flash packages with four die in each. We suspect the 512GB model also uses two packages with two die per package. The 2TB should uses four die packages but increase the package count to four.
This also means Intel could eventually build eight die flash packages with four packages to reach 4TB overall capacity, but such a product would significantly require more DRAM.