Samsung decided to bring its low-cost SSD 750 EVO to the U.S. after shipping it for months in Asia. The drive employs planar (2D) three-bit per cell NAND like the 840 EVO, but sees its controller upgraded with low-density parity check (LDPC) error correction technology found on the 850 family.
Samsung's 840 EVO arrived with great fanfare and generated a lot of excitement, becoming the best-selling SSD of all time. Over time though, a problem emerged. Customers found that older data on the drives would read back much slower than fresh data. Samsung fired back with a pair of firmware upgrades and we haven't heard much of the issue since then.
Although it was never officially mentioned, we suspect the underlying issue had to do with the 840 EVO's error correction engine. Samsung recently told us that the 840 EVO used BCH ECC technology, similar to many other SSDs with MLC flash. Newer drives with TLC NAND employ a technology called LDPC (low-density parity-check), which is a much stronger form of error correction that uses both hardware and software checks to recover bit errors.
The new SSD 750 EVO uses the 850 EVO's controller equipped with the more advanced LDPC ECC engine. The SSD was introduced in Japan and other Asian markets two months ago. We assumed the 750 EVO was Samsung's way of burning through a stockpile of planar (2D) NAND before transitioning to 48-layer 3D flash. The company recently stated that planar flash still has a future, and will not disappear from its line-up anytime soon. Samsung's 2D NAND is manufactured using 16nm lithography, and we've heard rumors of a 14nm node in development.
The 750 EVO also crams a 256MB DDR3 memory module in the same package as the MGX controller, which should reduce latency between the processor and its DRAM buffer. This is the first time we've seen the advanced design in a Samsung SSD.
The SSD 750 EVO only ships in two capacities: 120 and 250GB. Armed with a reworked MGX controller, 256MB of DDR3 and TLC flash, it fits in the SSD market's lowest-cost segment. At first we were thrown by the lack of visible DRAM, particularly since Samsung's controller package is similarly sized. Surely, though, the integrated buffer represents a step toward reducing costs.
Samsung's SSD 750 EVO claims some impressive performance figures. Its sequential read performance peaks at 540 MB/s. Both capacities also peak at 520 MB/s sequential buffered writes. And once again, Samsung manages to squeeze out 10,000 random read IOPS with minimal parallelism. This is attributable to the quad-plane design that doubles the available bandwidth between the controller and flash.
We're told that the 750 EVO targets system builders, and will allow integrators to add SSDs to low-cost notebooks and desktops. Its performance specifications are similar to the company's retail SSDs, but at much lower endurance levels. To compare, the 120GB 750 EVO is rated for 35 terabytes written. The same capacity 850 EVO sports a 75 TBW specification. The gap increases when you step up to 250GB (70 TBW versus 150 TBW).
You do get support for AES-256 full disk encryption, enabling TCG Opal v.2.0. The drives also work with Microsoft's BitLocker feature.
Pricing, Warranty And Accessories
The MSRP for the 120GB model is $54.99 and the 250GB capacity model is priced at $74.99. We expect to see more prevalent use of the SSDs among the tier-two system builders like Origin PC, CyberPower and AVA Direct. Most of those companies will handle warranty claims directly, but Samsung does back the drive with a three-year warranty capped at the TBW rating.
Our test samples arrived surrounded by bubble wrap. At first we assumed that Samsung would make this a white box release like its SM951 family. We later learned the 750 EVO will ship in retail packaging that includes documentation.
The 750 EVO does support Samsung's Magician software. Moreover, this series supports the company's Rapid Mode technology, which utilizes DRAM as a read and write cache. Samsung's Data Migration Tool is compatible as well, though neither software package is included and will need to be downloaded.
A Closer Look
According to Samsung, the 750 EVO will ship in a full retail box similar to the 850 EVO and 850 Pro models. At a glance, the 750 EVO looks like a standard 2.5-inch SSD with a slim 7mm z-height. This is the same chassis the company uses on other products like the 850 EVO.
Inside, we find a very small PCB hosting a handful of components. The images show the 250GB model with flash on both sides of the board. Again, the missing DRAM caught us off guard. Samsung didn't talk about its integration efforts during our call a week ago. But by pulling the DDR3 onto the controller's package, latency between the two components should be reduced. Samsung isn't talking about DRAM clock rates or timings, though.
The 120GB model loses the NAND package on the back of the PCB. This is a very low-cost design with low overhead.